Identification and localization of mobile robots

ABSTRACT

Autonomous mobile robots may communicate with each other to avoid hazards, mitigate collisions, and facilitate the operation that they are intended for. To enhance such cooperation, it would be highly advantageous if each robot were able to determine which robot, among a plurality of other proximate robots, corresponds to each communication message. The specific identity of each robot is generally unknown to the other robots if a plurality of robots are in range. Systems and methods provided herein can enable robots and other equipped devices to determine the spatial location of each other robot in proximity, by detecting a pulsed localization signal emitted by each of the other robots. In addition, each robot can transmit a self-identifying code, synchronous with the emitted localization signal, so that other robots can associate the proper code with each robot. After such localization and identification, the robots can then cooperate more effectively in mitigating potential collisions.

PRIORITY CLAIMS AND RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/782,672 titled “Infrared Pulse for Autonomous Vehicle Identification”filed Dec. 20, 2018, and U.S. Provisional Application No. 62/832,499titled “Autonomous Vehicle Localization System” filed Apr. 11, 2019, andU.S. Provisional Application No. 62/843,867 titled “Identification andLocalization of Mobile Robots” filed May 6, 2019, which are herebyincorporated by reference in entirety. This application is also relatedto U.S. Pat. No. 9,896,096, issued Feb. 20, 2018 entitled “SYSTEMS ANDMETHODS FOR HAZARD MITIGATION” and U.S. patent application Ser. No.16/148,390, filed Oct. 1, 2018 entitled “Blind Spot Potential-HazardAvoidance System” the contents of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The invention relates to systems and methods for short range locatingand identification of autonomous mobile robots.

BACKGROUND OF THE INVENTION

Autonomous self-powered self-directed mobile machines (“mobile robots”herein), are expected to greatly increase in the coming decades in areassuch as manufacturing, distribution, health care, commercial delivery,warehousing, security, scientific exploration, military, emergencyresponse, and many other areas. The development of powerful low-costcomputers, advanced imaging sensors, compact motors, fast networking(such as 5G and higher), vastly improved software, and efficient energystorage have enabled a wide range of autonomous mobile devices includingdrones, mobile carts, autonomous heavy equipment, airborne devices,underwater and surface marine robots, plus many others.

Coordination of mobile robots is a continuing challenge, especially whenthey are used in “swarms” or large numbers of intermingling devices.Typically each device is programmed to perform a task, such as movingitems around a warehouse, while avoiding collisions with other robotsand people. Mobile robots are not typically programmed to follow anyspecific route; instead, each robot proceeds in a different way. Foroptimal productivity and conflict avoidance, each robot should includemeans for communicating with other robots in proximity. For optimaleffectiveness, many of these communications should be individually andspecifically directed to a particular other robot, such as a wirelessmessage requesting to a particular other robot that it “Please movenorth one meter so I can get by”. However, current autonomous devicessuch as mobile robots lack the ability to determine which other robot,among a plurality of other robots in proximity, is associated with whichwireless message. Each robot may display markings or otheridentification, but such markings are often obscured by cargo or dust orother robots, for example. Coordination would be greatly improved ifeach robot could identify and localize each other robot in proximity.

What is needed is means for autonomous mobile robots to determine whichparticular robot among a plurality of proximate robots is associatedwith which identification code and which wireless message, so that theycould exchange specifically-addressed messages, greatly improve theircooperation, avoid interference and other problems, and improve theeffectiveness of the operation for which they are tasked.

This Background is provided to introduce a brief context for the Summaryand Detailed Description that follow. This Background is not intended tobe an aid in determining the scope of the claimed subject matter nor beviewed as limiting the claimed subject matter to implementations thatsolve any or all of the disadvantages or problems presented above.

SUMMARY OF THE INVENTION

In a first aspect, a system, mounted on a first robot, for localizing asecond robot, includes a wireless transmitter configured to transmit afirst wireless message; a localization signal emitter configured to emita first localization signal comprising pulsed energy synchronized withthe first wireless message; a wireless receiver configured to receive asecond wireless message from the second robot; a localization signaldetector configured to detect a second localization signal from thesecond robot, the second localization signal comprising pulsed energysynchronized with the second wireless message; and a processorconfigured to cause the localization signal emitter to emit the firstlocalization signal synchronously with the first wireless message, todetermine a direction of the second robot according to the secondlocalization signal, and to associate the second localization signalwith the second wireless message.

In a second aspect, a robot is configured to transmit a wireless messageconcurrently with a localization signal that includes one or more pulsesof sound energy or electromagnetic energy.

In a third aspect, a first robot is configured to determine whichparticular robot, among a plurality of robots proximate to the firstrobot, is associated with a particular identification code by detectingand determining the direction of a sonic pulse or an electromagneticpulse emitted by the particular robot.

In a fourth aspect, a system includes a wireless transmitter configuredto transmit a wireless message including a first identification code; alocalization signal emitter configured to emit a first localizationsignal including pulsed sonic or electromagnetic energy; a processorconfigured to cause the localization signal emitter to emit the firstlocalization signal having a temporal relationship with the firstwireless message; a wireless receiver configured to receive a secondwireless message and to detect a second identification code therein, thesecond identification code being associated with a particular robotamong a plurality of robots proximate to the system; a localizationsignal detector configured to detect a second localization signalcomprising pulsed sonic or electromagnetic energy; a camera configuredto image the plurality of robots proximate to the system; and aprocessor configured to determine which robot, among the plurality ofrobots, is associated with the second identification code.

This Summary is provided to introduce a selection of concepts in asimplified form. The concepts are further described in the DetailedDescription section. Elements or steps other than those described inthis Summary are possible, and no element or step is necessarilyrequired. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended foruse as an aid in determining the scope of the claimed subject matter.The claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

These and other embodiments are described in further detail withreference to the figures and accompanying detailed description asprovided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic indicating components and subsystems of anexemplary mobile robot, according to some embodiments.

FIG. 2 is a sketch showing two robots configured with exemplarylocalization systems, according to some embodiments.

FIG. 3 is a schematic showing exemplary pulses comprising an autonomousrobot identification and localization signal, according to someembodiments.

FIG. 4 is a schematic showing an exemplary sequence of wireless messagesand localization pulses versus time, according to some embodiments.

FIG. 5 is a schematic showing another exemplary sequence of wirelessmessages and localization pulses versus time, according to someembodiments.

FIG. 6 is a schematic showing another exemplary sequence of wirelessmessages and localization pulses versus time, according to someembodiments.

FIG. 7 is a sketch in perspective showing an exemplary localizationsystem, according to some embodiments.

FIG. 8 is a sketch in perspective showing another exemplary localizationsystem, according to some embodiments.

FIG. 9 is a sketch in perspective showing a different exemplarylocalization system, according to some embodiments.

FIG. 10 is a sketch in perspective showing an exemplary simplifiedlocalization system, according to some embodiments.

FIG. 11 is a top-view cross-section sketch showing the distribution oflocalization signal detector elements arranged around a circularenclosure, according to some embodiments.

FIG. 12 is a notional schematic of a circuit for detecting pulse-codedlocalization signals, according to some embodiments.

FIG. 13 is a sketch showing an exemplary image that includes severalmobile robots and a localization signal, according to some embodiments.

FIG. 14 is a sketch showing two exemplary images, one in visible lightand the other in infrared, according to some embodiments.

FIG. 15A is a sketch showing sequential positions of three prior-artrobots at successive times in which a collision occurs.

FIG. 15B is a sketch showing sequential positions of three robots havingexemplary localization systems, at successive times, in which acollision is avoided.

FIG. 16A is a sketch showing two prior-art robots in collision at anintersection.

FIG. 16B is a sketch showing two exemplary robots with localizationsystems avoiding a collision at an intersection.

FIG. 17 is a flowchart showing an exemplary method for two robots toexchange messages synchronized with localization pulses, according tosome embodiments.

FIG. 18 is a flowchart showing an exemplary method for two robots tospatially localize each other, according to some embodiments.

FIG. 19 is a flowchart showing an alternative exemplary method for tworobots to spatially localize each other, according to some embodiments.

FIG. 20 is a flowchart showing another alternative exemplary method fortwo robots to spatially localize each other, according to someembodiments.

FIG. 21 is a schematic sketch showing time traces such as oscilloscopetraces for various steps of an exemplary localization process, accordingto some embodiments.

FIG. 22 is a schematic sketch showing time traces such as oscilloscopetraces for various steps of an exemplary localization process withinterference, according to some embodiments.

FIG. 23 is a sketch of exemplary mobile robots configured to transportcargo, according to some embodiments.

FIG. 24 is a sketch of exemplary robots configured to performagricultural tasks, according to some embodiments.

FIG. 25 is a sketch of exemplary robots configured to clean up an oilspill, according to some embodiments.

FIG. 26 is a sketch of exemplary robots configured to fight a forestfire, according to some embodiments.

FIG. 27 is a sketch of exemplary robots configured to transport items ina hospital environment, according to some embodiments.

FIG. 28 is a sketch showing exemplary heavy equipment in a quarryenvironment, according to some embodiments.

FIG. 29 is a sketch showing exemplary mobile robots assisting anon-mobile robot, according to some embodiments.

FIG. 30 is a sketch showing exemplary mobile robots working in alogistical center, according to some embodiments.

FIG. 31 is a sketch showing an airport tarmac including exemplaryrobotic and semi-autonomous vehicles.

FIG. 32 is a sketch showing an emergency vehicle being blocked byprior-art vehicles at an intersection.

FIG. 33 is a sketch showing an emergency vehicle that includes anexemplary localization system direction other vehicles to get out of theway, according to some embodiments.

DETAILED DESCRIPTION

Systems and methods are disclosed that enable autonomously-operatedmobile robotic devices, or “robots”, to identify and localize othermobile and non-mobile robots in proximity. The disclosed “localization”systems and methods may enable robots to determine which particularrobot, among other proximate robots, is associated with a particularidentification code and/or which robot is transmitting a particularwireless message. Knowledge of which particular robot is associated witheach wireless message can greatly enhance the ability of the robots tocooperate with each other in avoiding collisions and enhancingefficiency. By knowing which particular robot, at which particularlocation, is associated with each identification code and each wirelessmessage, the robots can cooperate by communicating with each other,thereby avoiding conflicts and enhancing performance of their assignedtasks.

The localization systems and methods may include a localization signalcomprising pulsed energy which may be emitted by each of the mobilerobots. Other robots in the vicinity may detect the localization signaland may also determine the direction of the localization signal, therebydetermining the direction of the emitting robot relative to thereceiving robot. Each robot may also compare the direction of thelocalization signal to an image (such as a camera image) that shows theemitting robot, and may thereby determine which particular robot, amonga plurality of robots in proximity, emitted the localization signal. Thelocalization signal thus may serve as a semaphore indicating whichparticular robot is emitting the localization signal at any particulartime. In addition, the localization signal may be coupled with awireless message, so that other robots can receive the wireless messageand thereby establish which robot is transmitting that particularwireless message; namely, whichever robot is also emitting thelocalization signal. For example, the wireless message and thelocalization signal may be synchronous or simultaneous or otherwisecorrelated in time; the wireless message and the localization signal mayat least partially overlap in time; the wireless message may occur firstwith the localization signal beginning as the wireless message ends; thelocalization signal may start first and the wireless message may beginas the localization signal ends; or other temporal relationship betweenthe wireless message and the localization signal. Moreover, thelocalization signal may be emitted synchronously with, or responsive to,a particular icon in the wireless message, such as a word or code or bitpattern or other feature of the wireless message. As used herein,“synchronous” means having a temporal relationship, so that the wirelessmessage and the localization signal are synchronous when they have atemporal relationship with each other. For example, the wireless messageand the localization signal may be generated at the same time, or theymay partially overlap, or the localization signal may begin when thewireless message ends, or the wireless message may begin when thelocalization signal ends, or the localization signal my be emittedfollowing an indication in the wireless message that a localizationsignal is about to be emitted, or other temporal relationship thatenables a receiving robot to associate the localization signal with thecorresponding wireless message.

Each mobile robot may have an associated identification code. Preferablyeach identification code is unique or otherwise protected againstduplication among proximate robots. In some embodiments, theself-identifying code may be transitory and may be used only for animmediate set of interactions, while in other embodiments each robot mayhave a permanently assigned identification code, respectively. Thewireless message may include the identification code of the transmittingrobot, in which case the other robots can receive both the localizationsignal and the wireless message, and thereby associate theidentification code with the particular robot that synchronously emittedthe localization signal. By determining the identification code of eachrobot, the robots can subsequently communicate with each other usingwireless messages, advantageously with knowledge of which particularrobot is transmitting. The wireless message may also be “specifically”addressed to one of the robots when the message includes theidentification code of the intended recipient, along with an indicationthat the identification code is that of the intended recipient. Uponreceiving a message that includes the particular robot's identificationcode as the intended recipient, the particular robot with that specifiedidentification code can respond to the message. Other robots, whoseidentification codes do not match the specified recipient identificationcode, can then ignore the message. For example, the wireless message canmention the identification code of the transmitting robot to indicatewhich robot is the source of the message (along with an indication thatthe mentioned code is that of the transmitter robot), and may alsospecify the identification code of a particular recipient robot forwhich the message is intended (along with an indication that thespecified code is that of the intended recipient). In addition, eachrobot may store the identification code of each robot thus identifiedand, by tracking the other robots as they move, may be able to sendmessages to particular robots using the stored identification codevalues. With the identification codes thus stored, it may not benecessary to repeat the localization signal upon each wireless message,since the identification code of the transmitting robot is included inthe wireless message and the other robots already know which one isassociated with each code.

To consider a particular example, a first robot may transmit a wirelessmessage that includes its own identification code, and maysimultaneously emit a localization signal such as a light pulse or asound pulse. A second robot can detect the localization signal using,for example, a camera or a directional light detector or a directionalsound detector, and can thereby determine a direction toward the firstrobot relative to the second robot. In addition, the second robot cancompare the direction of the emitting robot to an image or other spatialdistribution that includes various robots in proximity, therebydetermining which of those robots is the first robot. The second robotthereby determines which particular robot is associated with theconcurrent wireless message as well as the identification code of theparticular robot. Each of the other robots can then perform thelocalization procedure likewise, by transmitting wireless messages andlocalization signals synchronously. The other robots can detect thewireless message and the localization signal, and can thereby localizeeach other robot. This localization processes may continue until each ofthe robots within range, or proximate to the first robot, have beenlocalized by the other robots, based for example on the number of robotsvisible to the first robot. Knowledge of which direction is associatedwith each wireless message provides improved situation awareness foreach robot. In addition, determining which spatially localized robot haseach identification code can enable much better cooperation between therobots by enabling them to send messages specifically to a particularother robot at a particular location.

Various modes of operation are possible. In a first embodiment (Mode-1),each robot emits a localization signal upon each wireless message. Otherrobots can determine which robot is transmitting each message bydetecting the concurrent localization signal. In a second embodiment(Mode-2), each robot emits an initial localization signal whilesynchronously transmitting a wireless message that contains thetransmitting robot's identification code. Other robots can receive thewireless message and the localization signal, record the identificationcode from the wireless message, and determine which particular robot isassociated with that identification code according to the direction ofthe localization signal. Each robot may communicate wirelesslythereafter, by including their identification code in each wirelessmessage, without having to repeat the localization process each time. Ina third embodiment (Mode-3), each robot emits a localization signal thatis modulated to encode the emitting robot's identification code, with orwithout a concurrent wireless message. Other robots can detect anddecode the encoded localization signal, and can also determine thedirection of the localization signal, thereby determining whichparticular robot is associated with the identification code. Thereafter,the robots can communicate wirelessly by including their identificationcode in each wireless message, without having to repeat the localizationsignal.

The localization system may include means for transmitting and receivingwireless messages such as Wi-Fi or Bluetooth transceivers, and means foremitting and detecting pulsed localization signals that indicate thedirection of the emitting robot such as infrared photodiodes andinfrared cameras, and means for determining the direction of eachlocalization signal such as a processor configured to analyze data fromeach of a plurality of collimated detectors aimed in differentdirections. The localization system may further include means forcomparing the direction of the localization signal to the directions ofrobots in range such as a processor configured to perform image analysison images from the infrared camera, and processor means for processingthe detection data to determine which particular robot is the emittingrobot. The system may include a processor configured to control thewireless transmission and reception processes, the localization signalemission and detection processes, the imaging process, and thedetermination of the direction of the localization signal. Each robot inrange that has a compatible localization system may participate in thelocalization procedure with each of the other robots. Each robot thusequipped may thereby obtain enhanced communication and cooperation withthe other participating robots.

While the examples provided herein are primarily directed toward mobilerobots, the same systems and methods are applicable to otherautonomously operated machines that are equipped with automatic meansfor emitting or detecting the localization signals. In some embodiments,the systems and methods may be applicable to communication betweenmobile robots and non-mobile devices such as fixed-location markers,fixed-site robots, and other devices that lack mobility. Embodiments maybe applicable to communications between two non-mobile robots thatinteract with each other by, for example, passing items between eachother or alerting each other of a condition change. Embodiments may beapplicable to vehicles capable of carrying humans, whether human-drivenor fully autonomous or semi-autonomous (such as automatic lane-keepingor cruise-control systems) or temporarily autonomous (such as emergencyintervention systems or automatic braking systems), so long as thevehicles include means for emitting and/or detecting localizationsignals. As autonomous vehicles increasingly intermingle withhuman-driven vehicles on roadways, mutual localization and cooperationwill be increasingly important to avoid conflicts. In addition, thesystems and methods may be applicable to communications between mobilerobots and humans carrying portable systems for emitting and detectingthe localization signals, thereby enabling the mobile robots to avoidinterfering with the proximate humans. In other embodiments, thelocalization signal or the wireless message may be configured to dosomething to the receiving robots, such as to cause the receiving robotsto stop in place, or change an operational parameter, or initiatecommunication with a central computer, or other action. In a furtherembodiment, an emergency vehicle such as a police car may include alocalization system to communicate with other non-emergency vehicles,for example to instruct the non-emergency vehicles to get out of the wayor to pull over in various circumstances. An emergency vehicle or othervehicle may be configured to specifically communicate with afixed-location robot such as a traffic signal or other device, and maycause the fixed-location robot to take an action such as to turn lightson or off, for example.

A mobile robot is “mobile” if it is self-propelled using an on-boardmotor with stored power, and has a means of locomotion such as wheels,tracks, propellers, articulated legs, wings, or the like. A robot is“autonomous” if it is operated solely or primarily by an on-boardprocessor (after being instructed as to task by a human or a remoteprocessor) with no or at most occasional instructions from a remoteprocessor and/or a human while performing the task. In the examples, a“first robot” is a particular robot in which the localization system isinstalled. The “second robot” is another robot proximate to the firstrobot. The second robot is “proximate” to the first robot if they areclose enough to cooperate in avoiding collisions. The second robot is“within range” of the first robot if they can exchange wirelessmessages. “Optical” means infrared or visible light. “RF” meansradio-frequency energy. An “electromagnetic pulse” is a pulse ofelectromagnetic energy such as visible light, infrared light, or RFenergy. The second robot is “detectable” to the first robot if thelocalization signal detector of the first robot can detect thelocalization signals (such as sonic or electromagnetic pulses) emittedby the second robot, and also the imaging device of the first robot canimage the second robot. A wireless message or other message is“specific” if the message is addressed to a particular recipient using,for example, an included identification code of the intended recipient.Thus a hailing message is not specific. The “localization procedure” isa method or process of transmitting wireless messages and associatedlocalization signals to other robots, and of receiving wireless messagesand localization signals from other robots, and determining which robothas transmitted each wireless message. “Localizing” a robot meansdetermining a direction toward the robot, and may also includedetermining which particular robot, among a plurality of detectablerobots, has emitted a localization signal. Both of the first and secondrobots, and any other robots in range, may have a localization systeminstalled and may determine which robot is associated with whichwireless message. As used herein, a “drone” is a self-propelled devicecapable of moving in two dimensions, such as horizontally, or threedimensions, such as vertically and horizontally. Examples of dronesinclude all unoccupied aerial vehicles (UAV's), including but notlimited to helicopters, hovercraft, airplanes, and/or autonomousaircraft of all descriptions. Further examples of drones includeunoccupied underwater vehicles (UUV's) such as submarines, mini-subs,submersible mobile devices, and/or underwater craft of all descriptions.An “imminent” collision is a possible future collision that may occurwithin a short time, such as 1 second or 10 seconds, if no avoidanceactions are taken. The localization signal is “pulsed” if it includesone or more separate intervals of emitted energy, such as sonic orinfrared or visible or RF energy, typically having a duration of 1nanosecond to 100 milliseconds.

Each robot may include an autonomous robot controller, such as aprocessor configured to plan and/or implement the motions of thatparticular robot. The autonomous robot controller, or other processor,may be configured to perform tasks cooperatively with other robots. Theautonomous robot controller, or other processor, may also be configuredto detect an imminent collision, and to cooperate with other autonomousrobots in avoiding the collision. Often such cooperation depends onknowing the location and identification of each of the other robots, orat least the directions of the other robots relative to the first robot.For example, the processor may be configured to select a first sequenceof actions for the first robot to implement and a second sequence ofactions for the second robot to implement, so that together they canperform a cooperative task or avoid a collision. However, suchcooperation depends on each robot having already determined where eachother robot is located. If the first robot cannot associate eachwireless message with a particular robot, then cooperation is hindered.The localization systems and methods according to the present disclosuremay provide an association between each robot's location and itswireless messages.

Turning now to the figures, FIG. 1 is a schematic of an exemplaryautonomous robot including sensors, processors, communications systems,and electromechanical systems. The sensors may include internal sensorsconfigured to measure the speed, acceleration, and/or bearing of therobot, the state of the battery and motor, among others. The sensors mayalso include external sensors configured to measure data about otherrobots using subsystems such as lidar, radar, sonic, and/or Dopplersystems to measure data such as distances and/or speeds of other robots.The sensors may include cameras in visible and/or infrared light,directional detectors based on sound or visible/IR light or RF, and anyother sensors on the robot. The terms “internal” and “external”generally refer to the location of aspects being measured by thesensors, and not necessarily the locations of the sensors themselves.

The processors may include one or more physical processing modules,configured to autonomously operate the robot. The processors may includea processor configured to drive the robot to its destination. Theprocessors may include a processor configured to plan and/or implement adriving route autonomously, according to the parameters of whatever taskthat the robot is to perform. The processors may include a processorconfigured to act cooperatively with other robots in performing tasks.The processors may include a processor configured to detect otherrobots, a processor configured to project robot motions forward in timeand thereby to detect an imminent collision, and a processor configuredto devise and calculate sequences of actions (such as accelerations,decelerations, and steering of the robot) to enhance cooperation and/oravoid interference and/or to avoid collisions with other robots. Aprocessor may be configured to implement the selected sequence ofactions by transmitting suitable signals to the motor and/or steeringand/or other subsystems of the robot according to the selected sequence.

The processors may include a processor configured to analyze wirelessmessages, and/or a processor configured to analyze localization signalsfrom other robots. A processor may be configured to determine whichrobot, among a plurality of robots proximate to the first robot,transmitted the wireless message. A processor may be configured toextract and record a robot identification code contained in the wirelessmessage and/or in the localization signal. A processor may be configuredto analyze a camera image or a directionalsound/ultrasound/infrared/visible/RF receiver or other directionaldetector data. A processor may detect robots proximate to the firstrobot spatially, such as robots represented in the image and/or detectedin the detector data. A processor may detect a localization signal inthe image and/or the detector data, and may spatially correlate thelocalization signal with a particular one of the other robots proximateor relative to the first robot, thereby determining which of the otherrobots emitted the localization signal. The image or directional datamay include both the localization signal and the proximate robotstogether; alternatively, the proximate robots may be imaged separatelyfrom the localization signal and subsequently correlated by, forexample, image analysis. The localization signal may be detected by adirectional detector which is an imaging type detector, such as aninfrared camera, or it may be detected by a non-imaging directionaldetector such as an array of separately-directed receivers such as anarray of sonic or optical or RF detector elements. When the localizationsignal detector is a non-imaging type, a processor may be configured toanalyze data from each of the separate directional detector elements,and thereby determine the direction of the localization signal. Aprocessor may be configured to track or follow the position or directionof another robot using, for example, image processing or other suitabletime-sequential measurement means. A processor may be configured toassociate wireless messages that include a particular robotidentification code with a particular robot that was previouslylocalized using an earlier localization signal.

The processors may comprise a computing environment optionallyassociated with non-transitory computer-readable media. The computingenvironment may include a computer, CPU, GPU, microprocessor,microcontroller, digital signal processor, ASIC, or other digitalelectronic device capable of analyzing data from sensors and preparing atask-cooperation or collision-avoidance sequence of actions, which mayinclude controlling the acceleration or deceleration or steering of thesubject robot according to the sequence of actions. The computingenvironment may include one or more processors, each processor beingconfigured to perform one or more of the computing tasks, including suchtasks as autonomously driving the subject robot, analyzing sensor data,calculating future positions of robots, detecting and avoiding apossible collision, selecting a sequence of actions to implement, andimplementing the sequence of actions. The non-transitorycomputer-readable media comprise any digital data storage media capableof storing instructions such as software instructions that, whenexecuted, cause the computing environment to perform a method forcausing the robot to perform a task solo or in cooperation with otherrobots, avoid interfering with other robots or humans or other items,avoiding a collision with any of the above, and reporting anyunresolvable problems to a central computer and/or a human supervisor.Examples of such media include rotating media such as disk drives andCD's, solid-state drives, permanently configured ROM, detachablememories such as removable drives and micro-SD memories, and the like,in contrast to more transitory media such as a computer's working memory(RAM, DRAM, cache RAM, buffers, and the like).

The communications module may include wireless means for communicationbetween robots and for communication with other receivers such as acentral supervisory computer, a human supervisor, a responsive boundarymarker or other marker, or other devices with which the robot cancommunicate. The communication module may further include receivers suchas GPS and internet receivers for weather and map data, and the like.The communications module may include a wireless transmitter and awireless receiver such as a radio-frequency transceiver. Thecommunications module may further include sonic or optical communicationmeans such as a light pulse or infrared pulse or sonic pulse or RF pulseemitter, configured to emit a robot localization signal such as a sonicor high-frequency RF or visible or infrared light pulse or a series ofsuch pulses. The communications module may further include alocalization signal detector configured to detect localization signalssuch as sonic or RF or visible or infrared pulses. The localizationsignal detector may be an imaging-type detector, or a directionaldetector, or otherwise configured to determine the direction of alocalization signal.

Means for wireless communication may include radio-frequencytransmitters and receivers, or alternatively transceivers. Opticalimaging means may include still or video cameras sensitive to infraredand/or visible light. The optical imaging means may be sensitive to thelocalization signal, and may thereby determine the direction of theemitting robot by detecting the direction of the localization signal.Alternatively, the optical imaging means may be sensitive to light fromrobots but insensitive to the localization signals, in which case aseparate localization signal detector may be included to detect theenergy pulse of the localization signal separately from the imaging. Ifso, such a localization signal detector may be a directional detectorconfigured to determine the direction of an arriving localizationsignal. Means for emitting localization signals may includelight-emitting diodes (LEDs) or other types of lamps, configured to emitone or more pulses, in the infrared or visible or other light bands.Alternatively, the localization signals may comprise pulses of sound orultrasound or other atmospheric vibrational energy (collectively,“sound” herein), in which case the localization signal emitter mayinclude a speaker or other sound generator, and the localization signaldirectional detector may include a plurality of spaced-apart microphonesin an array, or one or more directionally focused microphones or othersonic detectors, along with a processor configured to compare data fromeach sonic detector and thereby determine the direction of the emittingrobot.

The localization signal may comprise pulsed energy. For example, thelocalization signal may include one or more electromagnetic energypulses, such as an RF or infrared or visible light pulse or a series ofsuch pulses. Alternatively, the localization signal may include sonicenergy including one pulse or a series of sonic pulses, at one frequencyor a number of different frequencies. The localization signal detectormay be an imaging type sensor such as a camera or a plurality ofcameras, or a non-imaging directional detector or a plurality of suchdetectors, or other suitable detector configured to determine thedirection of the localization signal. The localization signal detectormay be configured to image the second robot concurrently with thelocalization signal on the same image, such as an image that recordsboth visible and infrared light, thereby determining directly from theimage which robot is the emitting robot. Alternatively, the localizationsignal detector may be configured to measure the direction of thelocalization signal, while an optional separate imager may be configuredto image the second robot, in which case the processor may be configuredto correlate the measured direction of the localization signal with theparticular robot in the image that is in the same direction as thelocalization signal, and thereby determine which robot is associatedwith which identification code.

The robot identification code is a code or data suitable for identifyingeach robot among other proximate robots. The robot identification codemay be a serial number, a random alphanumeric string, a string of bits,or other robot-identifying code. The identification code may includeinformation about the robot such as the type of robot, whether it isfixed or mobile, whether it is capable of emitting or detectinglocalization signals, and other properties of the robot. Preferably eachrobot has a unique identification code, or at least each code issufficiently detailed that two robots with the same identification codewould be unlikely to be in range of each other. In some embodiments, aparticular robot may be configured to determine when another robot hasthe same identification code as the particular robot, and responsivelymay change its own identification code permanently by, for example,adding a randomly selected number or letter to the end of its code. Inthis way, each robot can detect when another robot asserts the sameidentification code in a wireless message, and can then revise its ownidentification code, thereby causing each robot to have a different codethereafter. Each robot may transmit its identification code in awireless message. Each robot may emit a localization signal thatincludes the identification code encoded in, for example, a sequence ofpulses. Each robot may transmit a wireless message and a localizationsignal concurrently, or synchronously, or otherwise in a way thatassociates the wireless message with the localization signal. Forexample, the localization signal may be emitted during the wirelessmessage, such as continuously or periodically during the wirelessmessage, or the localization signal may be emitted upon a particularicon or word or other indicator within the wireless message, or at thebeginning or the end of the wireless message. Other robots may receivethe localization signal and the identification code concurrently, andmay thereby associate the wireless message with the emitting robot. Inaddition, robots that detect the localization signal and the associatedrobot identification code may record that association in, for example,computer memory or the like. After localizing a second robot, a firstrobot can then track the location of the second robot using, forexample, cameras. In addition, the first robot can send a wirelesscommunication specifically to the second robot by referring to thesecond robot's identification code in the wireless message along with anindication that the mentioned identification code is that of theintended recipient. The first robot can also indicate that the wirelessmessage is from the first robot by including the first robot'sidentification code in the wireless message, along with an indicationthat the included code identifies the first robot. The first robot candirect a wireless message specifically to the second robot and also showthat the message is from the first robot by including the first robot'sidentification code in the message with an indication that the firstrobot is the transmitting robot, and by including the second robot'sidentification code in the message with an indication that the secondrobot is the intended recipient of the message. With such specificity incommunication, the robots can cooperate with each other to perform theirtasks more effectively, avoid collisions and mutual interference, andfacilitate the operation in many ways.

The electromechanical module may include means for driving andcontrolling the robot. For example, the driving and controlling meansmay include motors, batteries, gears, and the like, along withelectrical, mechanical, hydraulic, and/or other types of linkagesconfigured to adjust the motor, linkages to apply the brakes, andlinkages to control the steering. The electromechanical module mayfurther include means for controlling tools or manipulators attached tothe robot, and means for performing whatever tasks the robot is intendedfor. The electromechanical module may further include indicators andalarms and if necessary transmitting equipment or circuitry and the liketo inform a supervisory computer or human of any problems encountered,especially unforeseen hazards and unresolvable problems.

FIG. 2 shows schematically two robots performing an exemplarylocalization procedure. The first robot 201 includes a wirelesstransmitter 203 transmitting a wireless message 207. The wirelessmessage 207 in this case is a “hailing” message, which is a wirelessmessage that invites other robots to perform a localization procedure.The hailing message, and preferably each wireless message from eachrobot, may include the identification code of the transmitting robot.The second robot 202 includes a wireless receiver 254 configured toreceive the hailing message 207 and other wireless messages. The firstrobot includes a chassis 209 with wheels 213, a motor 212, a battery210, a processor 211, a wireless receiver 204, and a localization signaldetector 206. The first robot 201 is further equipped with alocalization signal emitter 205, which emits a localization signal 208such as an infrared or visible flash or sound pulse or RF pulse.Typically, the localization signal 208 is emitted simultaneous with, orsynchronous with, or otherwise associated with, the wireless message 207that contains the first robot's identification code. Other robots canthen detect the localization signal 208 and thereby determine whichrobot is associated with that particular identification code, andthereby determine which particular robot is the first robot 201. Afterlocalizing each of the other robots, and determining which of thephysical robots is associated with which of the identification codes,each robot can thereafter collaborate and cooperate far more effectivelyto avoid interference and complete their tasks.

In the diagram, the second robot 202 is equipped with a localizationsignal detector 256 such as an infrared camera, and can thereby localizethe first robot 201 spatially, and thereby determine that the firstrobot 201 is the source of the localization signal 208 by comparing therobots in the image to the direction determined by the localizationsignal detector 256. Additionally, the second robot 202 includes awireless receiver 254, and can thereby associate the first robot'sidentification code with the direction of the first robot 201, andthereby identify (that is, associate the identification code of) andlocalize (that is, determine the spatial location of) the first robot201. The second robot 201 further includes a second processor 261, asecond battery 260, a second motor 262, a second signal emitter 255, asecond wireless transmitter 253, and a second chassis 259 with wheels263, and emits a second localization signal 258 and a second wirelessmessage 257. Instead of wheels 213-263 the first and second robots201-202 may have other means for locomotion such as tracks, legs,propellers, etc. Instead of a battery 210-260, the robots 201-202 couldhave other energy storage means such as hydrocarbon fuel, or they couldbe solar powered or otherwise powered according to the application anddesign.

After determining the location of the first robot 201 (by directionallydetecting the localization signal 208) and determining the first robot'sidentification code (by receiving a concurrent wireless message 207),the second robot 202 can then communicate with the first robot 201 withknowledge of the first robot's location relative to the second robot202. In addition, the second robot 202 can continue to track the firstrobot 201 optically, using visible light imagers or infrared cameras forexample, thereby determining where the first robot 201 is positionedrelative to the second robot 202 as long as the first robot 201 remainsin view of the imagers. If the second robot 202 loses track of the firstrobot 201, the second robot 202 can transmit a wireless message to thefirst robot 201 requesting that the first robot 201 again emit itslocalization signal. The second robot 202 can include the first robot'sidentification code in the message so as to specify that the first robot201 is the intended recipient of the message, and can also include thesecond robot's identification code in the message with an indicationthat this is the transmitting robot's code.

In most applications, it is not feasible to determine the direction of awireless message using a directional antenna, nor to form a directedwireless message using a collimated or focused beam at normal wirelessfrequencies in the radio band. Directional radiofrequency detection andbeam-forming generally require high frequencies and/or large rotatableantennas and/or phased arrays, all of which are expensive andcumbersome. Instead, a robot can send a wireless message specifically toanother robot by broadcasting the message omnidirectionally using a verybasic antenna, but including the identification code of the intendedrecipient in the message. Other robots that pick up the message can thendetermine, from the identification code, that the message is notintended for them, and can ignore it. In some applications, however, itmay be feasible to emit a localization signal using high-frequency RF.For example, large earth-moving equipment or an ocean vessel or anairliner, may be large enough to permit sufficiently separated antennas,and the necessary power is also often available. In such cases, eachrobot may detect the wireless messages directionally, that is, maydetermine the direction of the transmitting robot by measuring thedirection of the incoming wireless message energy. The wireless messagesthen serve as the localization signals by indicating which vehicle istransmitting each wireless message, in which case a separatelocalization signal, using a different type of energy, may not benecessary. Developers may select the type and frequency of thelocalization signal, from the list of pulsed sonic, RF, infrared, andvisible energy, or other pulsed energy, according to the applicationconstraints.

FIG. 3 is a schematic showing an exemplary localization signal thatincludes the identification code of the emitting robot in the signal.The localization signal includes a plurality of pulses of energy, suchas visible or infrared light or sound energy or other energy that can bedirectionally detected by a receiving robot. Since the identificationcode is included in the localization signal, it may not be necessary totransmit a concurrent wireless message, thereby reducing congestion inthe radio band. The identification code may be embedded or encodedwithin the localization signal as a series of short and long pulses, orpulses with short and long interpulse intervals, or using frequencymodulation, or other modulation configured to convey or indicate theidentification code of the emitting robot. The encoding may be in theform of Morse code, or ASCII, or BCD, or straight binary, or one of themany six-bit encodings, or other suitable encoding protocol thatincludes the symbols or elements of the emitting robot's identificationcode.

A receiving robot may detect the localization signal code pulses using ahigh-speed detector which is non-directional, while a different sensordetermines the direction of the localization signal without reading theindividual pulses. This may be economical since some directionaldetectors have insufficient time resolution to resolve the individualpulses, while some high-speed detectors lack imaging capability, but thecombination of a fast non-directional detector with a slower directionaldetector may enable the receiving robot to acquire the pulse-codedinformation and the directional information at the same time.

In the depicted example, the robot identification code is “ABC123”. Theexemplary coded localization signal also includes a “Start” code,followed by the encoded letters and numbers of the robot'sidentification code, and terminated by an “End” code. In this notionalexample, the Start code is two short pulses with a small separation, theEnd code is a single short pulse after a long space, and the variousletters and numbers are indicated by various long and short pulses withlong or short interpulse spaces. The pulses may have any duration, buttypically are very brief. For example, if the localization signal isoptical (visible or infrared) or high-frequency RF, the short pulses maybe 1 microsecond long and the long pulses may be 2 microseconds long,and likewise the interpulse periods may be 1 and 2 microsecondrespectively. In that case, a localization signal comprising a Startsymbol, seven symbols, and an End symbol, may be completed in a veryshort time such as 50-100 microseconds, depending on the encodingprotocol used. In another exemplary system, the signal may be a seriesof sound or ultrasound energy pulses, in which case the short pulses maybe 10 milliseconds in duration and the long pulses may be 20milliseconds, and the entire localization message may occupy a time ofless than 1 second. Use of higher sonic frequencies, such as ultrasonic100 kHz pulses, may enable shorter pulses such as 1-2 milliseconds andmay also simplify the directional determination due to the shorterwavelength of such high frequency sound pulses.

No specific coding is implied by the notional graphic depicted. Manydifferent coding protocols are possible. Preferably, all robots shoulduse the same encoding protocol so that they can interpret other robots'coded localization signals, or at least should be configured tocorrectly decode the encoded localization signals of the other robots ifthey use different encoding standards. An advantage of embedding theidentification code into the localization signals, rather than in aseparate wireless signal, may be to avoid cluttering the radio band withunnecessary wireless messages. If the coded localization signal isgarbled or otherwise not decipherable to another robot, or includescorrupt data or signal dropouts, then that other robot can transmit awireless message requesting that the coded localization signal should berepeated, or alternatively requesting that the code be sent by wirelessmessage instead.

As a further option, the localization signal emitter may be configuredto emit coded signals other than robot identification codes. Forexample, after detecting an imminent collision, a robot may emit asignal encoding “SOS” or “STOP” or other agreed-upon code to warn otherrobots to keep away. A robot may also use the encoded localizationsignal to indicate that it is a special robot such as anemergency-response robot or a supervisor robot for example, so that theother robots will know to keep away. The emitting robot may use adistinct frequency or color or other parameter of the localizationsignal to indicate something about the emitting robot, such as a bluelocalization signal for supervisor robots, or a low-frequency soniclocalization signal for humble laborer robots.

FIG. 4 is a schematic showing an exemplary sequence of wireless messagesand localization signals versus time. Depicted is a Mode-1 localizationprocedure in which a non-coded localization signal is emittedsynchronously with each wireless message. Accordingly, the schematicshows three wireless messages spaced apart in time, and threelocalization signals emitted concurrently with the wireless messages.Other robots can receive the wireless messages and can detect thelocalization signals, and thereby determine which robot is transmittingeach wireless signal. In Mode-1, no robot identification codes arerequired to determine which robot is transmitting, because each messageincludes a concurrent, or otherwise synchronous, localization signal.Optionally, however, identification codes may be included in Mode-1wireless messages so that the various robots can then send messagesspecifically to each other.

FIG. 5 is a schematic showing another exemplary sequence of wirelessmessages and localization signals versus time. Depicted is a Mode-2localization procedure in which each wireless message includes the robotidentification code (“CODE”) of the transmitting robot along with anindicator (“INDICATOR”) indicating that the code identifies thetransmitting robot, as opposed to a random string, an instruction, orother data. A localization signal is emitted synchronously with thefirst wireless message, and subsequent wireless messages do not have anassociated localization signal. Instead, a receiving robot can determinethe location of the transmitting robot upon detecting the first message(according to the direction of the associated localization signal), andcan then record the identification code received in that first messageand indicated by the indicator in the first message, and thereafter candetermine which robot is the source of each subsequent wireless messagethat includes the same identification code.

The robot identification code may be included in a wireless message atthe beginning of the wireless message, or at the end, or elsewherewithin the wireless message along with an indicator that indicates thatthe code is the transmitting robot's identification code. For example,the transmitting robot can send a message that includes passages such as“I am robot number 3.14159. This message is intended for robot 2.71828.Please move one meter north.” In that case, the portion “I am robotnumber” is an indicator indicating that the transmitting robot'sidentification code follows, and the portion “3.14159” is theidentification code. The portion “This message is intended for” is anindicator indicating that the message is specifically intended foranother robot, and that the recipient's identification code follows. Theportion “robot 2.71828” is the identification code of the intendedrecipient. Thus a wireless message can mention the identification codeof the transmitting robot along with an indicator indicating that thementioned identification code is that of the transmitting robot, and canalso specify the identification code of the recipient robot along withan indicator indicating that the specified code is that of the intendedrecipient.

Alternatively, the self-identifying code may be placed at a particularplace in the message, in which case an explicit indicator may not beneeded. For example, by convention, the self-identifying code may beplaced at the end of the message (resembling a signature), in which caseother robots may be configured to automatically interpret a terminalcode in a message as the sender's identification code. Thus the“indicator” is simply the position of the identification code at the endof the message. Likewise, the intended recipient's code may be placed atanother particular place in the message, without providing an explicitindicator. For example, the intended recipient's code may be placed atthe beginning of the message (resembling a salutation), so that otherrobots may be configured to interpret a leading identification code in amessage as that of the intended recipient. With these conventions, theexample message may read as follows: “Robot 2.71828, move north 1 meter.Robot 3.14159.” With these conventions, the robots may communicate moreeasily and with less bandwidth-loading, using shorter messages.

As a further alternative, the transmitting robot can send wirelessmessages without mentioning its own code; however in that case thereceiving robots would have no way to determine which robot the messagesare coming from. The receiving robot can then send a wireless hailingmessage requesting that the transmitting robot again emit a localizationpulse.

FIG. 6 is a schematic showing another exemplary sequence of wirelessmessages and localization signals versus time. Depicted is a Mode-3localization procedure in which the transmitting robot's identificationcode is embedded in a localization signal, for example by modulating avisible or infrared or RF or sonic signal. Other robots can detect thelocalization signal, and decode the embedded robot identification code,and thereby determine the location of the emitting robot and also recordthe identification code of the emitting robot. As shown, there is nowireless message associated with the localization signal. Transmittingthe identification code in the localization signal, rather than by aseparate wireless message, may prevent overloading of the radiofrequencyspectrum while efficiently broadcasting each robot's location andidentification to other robots. After the initial localization,subsequent communication can be by wireless messages that include theidentification codes without further localization signals. However, if anew set of robots arrives in range, the first robot may emit its codedlocalization signal once again, to introduce itself to the new arrivals.

FIG. 7 is a perspective sketch of an exemplary localization system 700,which may be mounted on a first robot (not shown), and configured toemit and receive localization signals. The localization system 700 mayinclude a localization signal emitter 705 configured to emit alocalization signal 708. For example, the localization signal 708 mayinclude one or more pulses of visible or infrared light, and thelocalization signal emitter 705 may include one or more LEDs or otherlamps; alternatively, the localization signal 708 may include sound orultrasound and the signal emitter 705 may include speakers or soundgenerators or the like. As a further alternative, the localizationsignal 708 may include high-frequency RF and the signal emitter 705 mayinclude an antenna array. In some embodiments, the localization signalemitter 705 may extend substantially around 360 degrees and may emit thelocalization signal 708 substantially all around the subject robot,thereby being visible or detectable to other robots regardless of theirazimuthal position relative to the first robot. Such an emitter is“omnidirectional” if the emitted signal energy is distributed throughoutall or substantially all horizontal directions (or, in the case of adrone or underwater robot or other robot that travels in threedimensions, the emitted signal energy may be distributed throughout a 4πsolid angle or “isotropically”). A single central emitter 705 may beprovided as shown; alternatively, a plurality of emitters may beprovided, such as two emitters on the ends of a robot and configured toemit around 180 degrees each, or four emitters on the corners of therobot and configured to emit around 90 degrees, or other combinationthat, together, covers all or substantially all of a 360-degree range ofhorizontal angles (or a 4π solid angle for drones and the like).

The localization system 700 may further include a localization signaldetector 706. The detector 706 may be an omnidirectional detector whichis configured to detect localization signals from all or substantiallyall horizontal directions (or all spherical directions for athree-dimensionally mobile robot). Alternatively, the detector 706 maycomprise a plurality of separate detectors 715 positioned or aimedaround the robot and configured to detect localization signals from all,or substantially all, directions in two (or three) dimensions. Inaddition, the localization signal detector 706 may be a high-speedoptical pulse detector, configured to detect the individual pulses of apulse-coded localization signal from other robots. The main purpose ofthe detector 706 may be to detect localization signals with sufficienttime resolution to resolve individual pulses and thereby to read therobot identification code which is embedded or encoded or modulated inthe localization signal. In some embodiments, the detector 706 may befurther configured to determine the direction of the localizationsignal. For example, the direction-sensitive localization signaldetector 706 may include a large number of photodiodes 715 ormicrophones or antennas, each configured to detect energy in thewavelength of the localization signal, and distributed around thedetector 706 with each sensor element 715 being aimed or focused orcollimated in a different direction. Alternatively, the sensor elements715 may be an array such as a sonic receiver array or a high-frequencyRF antenna array for example. The detector 706 may thereby detectlocalization signals substantially all around the horizontal plane (oraround the 4π sphere), and also may indicate the direction of theemitting robot according to which of the sensors 715 registered thedetection. Photodiodes sensitive to visible and/or infrared light withsub-microsecond time resolution are readily available, as aremicrophones sensitive to sound and ultrasound at high frequencies.

The localization system 700 may further include an imaging device 718,which may have lenses 714 pointing in various directions, configured toform images of robots and other items around the first robot. Thus, theimaging device 718 may detect the various robots and their locations ordirections, while the directional detector 706 may detect the incominglocalization signal and its direction according to which sensor 715 wasactivated. Thus, the localization system 700 can determine which robotemitted the localization signal. In addition, by correlating the imagewith the code that was observed by the detector 706, the emittingrobot's identification code can be correlated with the physical robotthat was recorded in the image. Concordance of the localization signalwith one of the imaged robots can thereby determine both theidentification code and the spatial location of that emitting robot.

To consider a specific example, the localization signal 708 may comprisea plurality of brief pulses in which the emitting robot's identificationcode is embedded. The localization signal emitter 705 may include asufficient number of infrared LEDs pointing around the subject robot tocover substantially all horizontal directions. The localization signaldetector 706 may include a sufficient number of infrared-sensitivephotodiodes or phototransistors or other suitable sensor elements 715,distributed around the periphery and pointed in various directions todetect localization signals coming from substantially any directionaround the first robot. Each sensor element 715 may be configured tohave sufficient time resolution and sensitivity to resolve individualpulses of the incoming coded localization signals. The imager 718 may bea visible-light camera or a near-infrared camera or other suitableimaging device, configured to image robots around the first robot anddetermine the spatial locations of those robots.

As an alternative, the localization signal emitter 705 may have a singleinfrared source along with a conical reflector or other optical elementsconfigured to distribute the localization signal 708 horizontally aroundthe first robot. Other suitable optical arrangements are also known.

FIG. 8 is a perspective sketch of another exemplary localization system800. In this example, the robot identification code is again embedded inthe localization signal. However, the localization signal detector isnot directional; instead it is configured to read the incomingidentification codes omnidirectionally. At the same time, an imager suchas a camera is sensitive to the localization signal and also to thevarious robots in view of the imager. The imager thereby images both thelocalization signal flash and the robots in a single image, and therebyidentifies the emitting robot as the one with the flash upon it.

More specifically, the localization system 800 may include anomnidirectional emitter 805 configured to emit a localization signal 808that includes an identification code therein. In addition, a high-speedomnidirectional detector 806 may be configured to detect other robots'localization signals and to read the codes therein, such as measuringthe width and timing of a series of pulses that form the incominglocalization signals. Thus, the detector 806 may read the code but,since it is omnidirectional, the detector 806 does not determine whichrobot emitted the code, in this example. Concurrently, an imager 818such as a camera with lenses 814 may be configured to record the robotsand the localization signal on the same image. The localization signalmay appear as a flash superposed on one of the robots. For example, theimager 818 may be a camera sensitive to both visible and infrared light.Thus, the imager 818 may determine which particular robot emitted thelocalization signal, while the detector 806 reads the code. Thus, theemitting robot's location and code are both determined. Imaging devicestypically record a scene in frames by accumulating light or other energyduring a predetermined brief interval. In that case, the incominglocalization signal (which may be very brief) may appear in only asingle frame, such as the frame which was acquired when the fastlocalization signal was detected by the detector 806. By seeking thelocation of a single-frame transient feature synchronous with thedetected localization signal, the system 800 can thereby determine whichrobot emitted the localization signal.

FIG. 9 is a perspective sketch of an exemplary localization systemconfigured to image robots and other items, and simultaneously to imagean incoming non-coded localization signal, using two separate imagingdevices. The system 900 includes a localization signal emitter 905emitting a localization signal 908 such as an infrared flash. In thisembodiment, the localization signal 908 is pulsed but is not encoded;instead, the identification code is provided separately by a concurrentwireless message.

The system 900 further includes two imaging devices: a localizationsignal imaging device 906 such as an infrared camera, and a generalscene imaging device 908 such as a visible-light camera. Thelocalization signal imaging device 906 may be configured with lenses 914or other directional items, and configured to detect and imagelocalization signals from other robots. The scene imaging device 908 maybe configured with further lenses 924 to image around the first robot todetect the direction or location of other robots, and specifically toobserve whichever robot is emitting the localization signal that thelocalization signal imaging device 906 has detected. By correlating thevisible and infrared images, the depicted system 900 may localize theemitting robot spatially, and by correlating that robot with a robotidentification code (provided in a concurrent or synchronous wirelessmessage) the emitting robot can be associated with the identificationcode. In addition, the system 900 may track the emitting robot using,for example, the scene imaging device 918, and the system 900 maymaintain and update the direction or positional information about theidentified robot as it moves.

FIG. 10 is a perspective sketch of another exemplary localization system1000 in which the localization signal includes sound pulses. An imagingdevice 1018 such as a camera is configured with lenses 1014 to viewaround the first robot and thereby to detect other robots. Thelocalization signal in this case is a single brief pulse of ultrasoundemitted by a sonic antenna including three linear sonic antenna elements1005. To emit a sonic localization pulse, the three sonic antennaelements 1005 are driven in-phase at a frequency, such as 50 kHz or 100kHz, and thereby emit sound waves substantially horizontally around thefirst robot. To detect sonic localization pulses from other robots, thethree antenna elements 1005 are configured to convert incoming soundwaves to electrical signals, which are then amplified separately andcompared to each other, so as to determine the relative arrival times ofthe sound waves at each of the sonic antenna elements 1005. The relativetiming of the waves at the three sonic antenna elements 1005 indicatesthe azimuthal direction of the emitting robot in two dimensions,relative to the first robot. Then, comparison of that azimuthaldirection with an image from the imaging device 1018 thereby localizesthe emitting robot and associates it with the identification code in theconcurrent wireless message using the transceiver 1003.

FIG. 11 is a notional top-view cross-section sketch of an exemplarydirectional detector 1106 for detecting localization signals anddetermining their directions. The depicted system 1106 comprises a largenumber of sensor components 1115 mounted on a circular frame 1109 andaimed at different horizontal directions and configured to detect thewavelength and timing of localization signal pulses. Each sensorcomponent 1115 has a limited field of view indicated by dashed lines1116, so that an arriving localization signal is observable in only oneof the sensor components 1115 (or perhaps divided between two adjacentsensor components 1115). The direction of the emitting robot is thusdetermined by which of the sensor components 1115 detected thelocalization signal, and if two adjacent sensor components 1115 detectedthe same localization signal, the direction of the robot may bedetermined by averaging, interpolation including weighted interpolation,or other combination of the two detecting sensor components 1115.

FIG. 12 is a notional circuit schematic of one of the sensor components1115 of FIG. 11. A localization signal symbolized as an electromagneticwave 1208 is incident on an optical filter 1224 configured to passwavelengths that include the localization signal 1208, which in thiscase is optical. A lens 1225 focuses the energy onto a biased photodiode1226, causing a current flow that transits through a high-pass or otherelectronic filter 1227 which may be configured to admit frequenciescorresponding to the pulses of a coded or non-coded localization signalwhile blocking other frequencies such as noise and backgrounds. Then again stage, such as an operational amplifier 1228, amplifies the rapidsignal, and a voltage discriminator 1220 or the like can sharpen theshape and timing of the detected pulses. A processor such as amicrocontroller 1223 can then record the pulse or pulses, and canindicate that the localization signal 1208 has been detected. Also, ifthe localization signal 1208 includes an embedded robot code, themicrocontroller 1223 may be configured to decode it.

FIG. 13 is a notional sketch of an exemplary image 1317 obtained by animaging device such as a camera, configured to record both alocalization signal and the emitting robot in the same image. In theimage 1317, four robots 1302 are seen, each with a localization signalemitter 1305 and a wireless transceiver 1303. One of the robots 1301 isemitting a localization signal 1308 which appears along with theemitting robot 1301 in the image 1317. The imaging device thusdetermines which of the robots is emitting the localization signal 1308.Also, if a robot identification code is provided in a concurrentwireless message or encoded in the localization signal 1308, then therobot identification code can be associated with the particular robot1301 that emitted the localization signal 1308.

FIG. 14 is a notional sketch of two exemplary images 1417-1418. Thefirst image 1417 is a visible-light image showing four robots 1402, eachof which includes a localization signal emitter 1405 and a wirelesstransceiver 1403. A particular robot 1401 is emitting a localizationpulse in the infrared, but this does not show up on the first image 1417which only shows visible light. The second image 1418 is an infraredimage showing the localization signal 1408, but does not show the robots1401-1402. When combined, the two images 1417-1418 thereby indicatewhich robot is the emitting robot.

FIG. 15A is a schematic showing how a collision scenario may proceedaccording to prior art, in which the robots do not have localizationsystems such as those disclosed herein. The robots therefore have no wayto identify and localize the other robots. Consequently, little or nocooperation can be arranged, even in an emergency. The depicted scenarioinvolves successive views of three robots at successive times. Thescenario ends in a needless collision.

At time t=0, in a passageway demarked by lines 1530, there are shownthree icons representing a first, second, and third robot 1501-1503. Ablock arrow such as 1516 indicates how each robot is moving.

The passageway is repeated at a later time t=T1 such as 1 second. Thus,the figure shows how each robot moves during the scenario.

Initially, at t=0, the first robot 1501 is approaching from the left andthe two other robots 1502 and 1503 are approaching from the right. Thereis not enough space between the two robots 1502-1503, nor on eitherside, for the first robot 1501 to pass. Therefore, the first robot 1501sends wireless messages to the other robots suggesting that one of themshould shift to the right and the other one should shift to the left toavoid a collision. However, since the robots lack a system forlocalizing each other, the first robot 1501 has no way to specify whichof the other two robots 1502-1503 should move left or right.Consequently, at t=T1, the second robot 1502 has mistakenly assumed thatit was supposed to shift left, and the third robot 1503 has mistakenlyshifted right, resulting in a three-robot collision, or at least anunnecessary blockage and mutual interference among the robots.

FIG. 15B shows a similar scenario, but now the robots includelocalization systems according to the present disclosure. Bycooperating, they manage to avoid the collisions.

The first, second, and third robots 1551-1553 now include localizationsystems 1519, indicated by a star, and therefore can determine theidentification codes of each other robot specifically, and can sendwireless messages to each other specifically. Accordingly, the firstrobot 1551, after first exchanging localization signals andidentification codes with the other robots 1552-1553, then sends awireless message specifically to the second robot 1552 suggesting thatit shift to its right, and another wireless message specifically to thethird robot 1553 suggesting that it shift to its left. At the time t=T1,the second and third robots 1552-1553 have moved as shown by dottedarrows, thereby opening space between them for the first robot 1551 topass by. In this way, the robots 1551-1553 have used their localizationsystems 1519 to avoid an unnecessary collision and removed a temporaryblockage peacefully. Most interference situations among autonomousmobile devices may be resolved faster and better, or avoided altogether,by communicating with knowledge of which device is where.

FIG. 16A is a sketch showing how robots lacking a localization systemcan collide in an intersection defined by opaque walls. The first andsecond robots 1601-1602 approach the intersection and, since they cannotspecifically communicate with each other, are unable to stop in time toavoid a collision.

FIG. 16B is a sketch showing how robots 1651-1652 that include exemplarylocalization systems 1619 can avoid such a collision. The two robots1651-1652 are still unable to see each other using their imagers due tothe walls, but since they have previously determined each other'sidentification codes, they can communicate specifically to each other.For example, the first robot 1651 knows that the intersection isdangerous due to poor visibility, and therefore may send a wirelessmessage to any robots in proximity stating that it is approaching theintersection. The second robot 1652 receives the message and, since itis also approaching the intersection, may deduce that a collision may beimminent. Therefore, the second robot 1652 may send a wireless messagespecifically to the first robot 1651, requesting that it hold back untilthe second robot 1652 passes. The first robot 1651 obligingly holdsshort of the intersection until the second robot 1652 has passed, andthen proceeds. In this way the robots 1651-1652 have avoided anunnecessary collision.

FIG. 17 is a flowchart showing an exemplary localization procedure inwhich each robot emits a localization signal synchronously with eachwireless message (termed Mode-1 above). Robot identification codes arenot included in this example, although the robots may haveidentification codes and may exchange them aside from the actions shownhere. The actions of robot-1 are shown on the left and robot-2 on theright.

In the depicted example, robot-1 transmits (1701) a first wirelessmessage and, at the same time or otherwise synchronously, emits a firstlocalization signal such as a visible or infrared pulse. Robot-2receives (1702) the first wireless message and the first localizationsignal, and determines (1703) which robot, of several proximate robots,is the robot-1, based on a camera image that shows the firstlocalization signal while the first wireless message was received.Robot-2 transmits (1704) a second wireless message synchronously with asecond localization signal. These are received (1705) by the robot-1,which thereby localizes robot-2. The robots may continue to communicatewirelessly (1706), while continuing to emit localization signalssynchronously with each wireless message, thereby indicating which robotis associated with each wireless message. If the other proximate robotstransmit wireless messages, they may emit synchronous localizationsignals in the same way, thereby avoiding any confusion as to whichrobot is transmitting each message.

FIG. 18 is a flowchart showing an exemplary Mode-2 localizationprocedure in which multiple wireless messages are exchanged inpreparation for the localization signal. The actions of robot-1 areshown on the left and robot-2 on the right. Robot-1 initiates (1801) thelocalization procedure by “hailing” other robots, that is, bytransmitting a wireless message that identifies robot-1 as an autonomousrobot and requests a mutual localization procedure with any robots inrange. Each robot-1 message includes robot-1's unique identificationcode (“code-1” in this example). Robot-2 responds (1802) with a wirelessmessage indicating that it too is autonomous, and in the same messageprovides its identification code-2. Robot-1 sends (1803) anotherwireless message indicating that it is about to emit a localizationsignal, and emits (1804) a non-coded localization signal, such as asingle ultrasound or infrared pulse. Since the robot identification codewas provided in a wireless message, it is not necessary to embed theidentification code-1 in the localization signal. Also, the localizationsignal is synchronized with a robot-1 message, thereby associating thecode-1 with robot-1. Robot-2 detects (1805) robot-1's localizationsignal using, for example, a directional detector or an array ofdetectors or an imaging device sensitive to the type of energy in thelocalization signal, such as an infrared-sensitive camera for aninfrared pulse or an array of microphones for a sonic localizationsignal, thereby localizing robot-1 and associating it with code-1.

Robot-2 transmits (1806) a wireless message indicating that itslocalization signal is forthcoming, along with its identificationcode-2. Robot-2 emits (1807) a localization signal such as anotherinfrared pulse. Robot-1 detects (1808) robot-2's localization signal,using an infrared camera or microphone array for example, therebylocalizing robot-2 spatially and associating robot-2 with identificationcode-2. Thereafter, robot-1 and robot-2 can continue to communicate(1809) while spatially tracking each using, for example, cameras andimage analysis, or by radar, or other suitable means for following thepositions of robots. The robots can thereby cooperate with each otherusing the knowledge of where each of the robots is located. With suchcooperation, collisions can be avoided and autonomous tasks can befacilitated generally.

FIG. 19 is a flowchart showing a simpler exemplary localizationprocedure, in which the robot identification code is provided in asingle wireless message instead of back-and-forth handshaking. Robot-1transmits (1901) a wireless hailing message that includes itsidentification code-1, and simultaneously emits a non-coded localizationsignal such as a single infrared pulse. Robot-2 receives (1902) thewireless message and images the localization signal using, for example,an infrared camera. Robot-2 records the code-1 and the position ofrobot-1, thereby localizing robot-1. Robot-2 transmits (1903) a wirelessmessage with its code-2 and simultaneously emits a non-codedlocalization signal such as an infrared pulse. Robot-1 receives (1904)the wireless message and the localization pulse from robot-2, therebylocalizing it. The two robots can collaborate (1905) with knowledge oftheir relative positions.

FIG. 20 is a flowchart showing another exemplary localization procedure,in which the identification code is embedded in the localization signalrather than a wireless message (Mode-3). Robot-1 detects (2001) that anunidentified robot-2 has entered its proximity and emits (2002) a codedlocalization signal, such as a series of infrared pulses with itsidentification code-1 embedded therein. Robot-2 detects (2003) thelocalization signal, and images robot-1 along with the localizationsignal, thereby determining the location of robot-1 as well as itsidentification code-1. Robot-2 emits (2004) a coded localization signalthat includes its identification code-2, and robot-1 receives (2005)that signal while imaging robot-2, thereby localizing robot-2 inassociation with its identification code-2. With that knowledge, therobots can communicate wirelessly (2006) using the known identificationcode-1 and code-2, while continuously tracking the other robot byoptical imaging, or radar, or other suitable tracking means. Eitherrobot can request (2007) another localization signal wirelessly if thetracking is interrupted. An advantage of this version may be that itavoids cluttering the radio bandwidth with unnecessary wirelessmessages, since no wireless messages are involved until one of therobots has a need for communication. Another advantage may be that therange is self-limiting, in that any pair of robots that cannot see theother robot's localization signal would be considered out of range.

The localization procedure may be configured to avoid signal contentionor overlap, a situation in which two robots attempt to transmit wirelessmessages or localization signals at the same time. For example, signalcontention can occur if robot-1 transmits a hailing message and twoother robots respond at the same time. To avoid such interference, eachrobot may be configured to wait for a random or pseudorandom waitinginterval after receiving the hailing message, and then to respond if noother robot has responded sooner. (Random and pseudo-random are treatedas equivalent herein.) In that way, message overlap is largelyprevented. If a robot is prepared to respond to the hailing message, butis forced to withhold its response due to interference, then thewithholding robot may wait until the in-progress localization procedurehas concluded, and may then respond. In addition, to avoid creating asecond contention situation, the withholding robot may provide a secondrandom-duration waiting period. For example, after detecting that thein-progress localization procedure has concluded, the withholding robotmay then wait an additional random interval, and then may initiate itsresponse if a third robot has not already done so. Thus, the randomizedwaiting intervals can avoid cascaded contention and interference.

The random or pseudorandom waiting intervals may be arranged accordingto a random-number algorithm executed by a processor, such as acalculation that selects a number of milliseconds of waiting time, orotherwise. The algorithm that provides the random interval may beconfigured to populate the random intervals uniformly within apredetermined range of waiting times, such as between 1 second and 2seconds. Such a predetermined interval, during which an event can betriggered, is sometimes called a “gate”. Thus a first robot may beconfigured to receive a wireless message from a second robot, and thento wait for a predetermined waiting interval to avoid post-messagesignal contention with other robots, and then to prepare a gate intervalof a predetermined length, and to select a random time within that gateinterval to emit its responsive second wireless message.

The robots may be configured to adjust their random waiting intervalsaccording to various conditions. For example, if a robot has been forcedto withhold its response to a hailing message, that robot may thenshorten its random waiting interval on the next try, thereby increasingthe likelihood that it can beat the other robots. Each robot may beconfigured to initially start with a rather long waiting interval suchas between 500 and 1000 milliseconds, on the first attempt. Then, if therobot is prevented from responding due to other messages starting first,the withholding robot may shorten the next random waiting interval tobetween 250 and 500 milliseconds. After each successive inhibition, therobot may halve its range of random waiting intervals, and continuelikewise until the withholding robot is finally able to initiatecommunication without interference. In this way, each robot is likely tohave a turn, and the robots that have waited longest automaticallybecome the first in line for the next attempt. After finally completinga full localization procedure, each robot may restore its random waitingrange back to the initial long setting, so that other waiting robots canthen have their turn.

The robots may be configured to complete the full localization procedurein a short time, such as 0.1 or 1 or 10 or 100 milliseconds using, forexample, fast electronic and optical or ultrasound components. In mostsituations, even if dozens or hundreds of other robots are in range,most or all of the robots within range may then be able to completetheir localization procedures in 1 second or a few seconds, typically.In addition, if each robot is configured to embed its identificationcode in the localization signal rather than in wireless messages, theperiod of contention may be extremely short, such as only 50-100microseconds in some embodiments, by emitting a correspondingly brieflocalization signal.

FIG. 21 is a schematic chart showing the timing of various actionspertaining to a first robot's response to another robot's hailingmessage. The horizontal axis is time, and each line or item representsan action or a demarked time interval. In the first line, the firstrobot transmits a hailing message during a time indicated by the pulsemarked HAIL. The line marked GATER represents an electronic clock in thefirst robot that is configured to wait, after the end of the hailingmessage, for a predetermined time interval WAIT, and then to open a gateinterval GATE during which the first robot can respond to the hailingmessage if no interference is present. A third robot is present asindicated by the line THIRD; however, the third robot remains silent inthis case; hence the line marked THIRD is flat. The first robot thenresponds to the hailing message at a random (or pseudo-random orotherwise computed) moment within GATE. In summary, the first robotavoids interference with other robots by waiting for the predeterminedWAIT interval, thereby giving other robots a chance to respond. Inaddition, the first robot may wait a second random interval after theGATE has opened, to avoid pile-up that could occur if multiple robotsall initiated messages at the end of the predetermined WAIT interval.The second interval is marked WAIT-2.

FIG. 22 is a similar schematic, but this time the third robot beginstransmitting before the subject robot does, and therefore the firstrobot has to abort its response and wait until the intruding robotfinishes. The HAIL message is shown in the first line. The first robot'stiming is shown in the second line GATER, starting with thepredetermined WAIT interval and then opening a gate. However, in thisexample, the third robot begins transmitting a message while the firstrobot's gate is open but before the first robot has startedtransmitting. Therefore, the first robot, detecting the interference,immediately closes its gate interval, which is labeled as TRUNCATED GATEfor that reason.

After the interfering message has completed, the first robot thenprepares another predetermined delay labeled SECOND WAIT. Since thefirst robot was forced to withhold its message, the SECOND WAIT intervalis chosen to be shorter than the original WAIT interval. The first robotthen opens another gate interval labeled SECOND GATE, during which aresponse may be transmitted at some random moment. The last line shows,in dash, the originally planned response message labeled ABORTEDRESPONSE, which was aborted due to the interference. The final message,labeled RESPONSE, was then transmitted within the SECOND GATE. TheSECOND WAIT interval is configured to be shorter than the original WAITinterval so that the first robot would have an increased likelihood ofbeing able to start its RESPONSE before another robot beginstransmitting. Thus the first robot is configured to wait, afterreceiving the hailing message, for a first waiting interval beforearranging its gate interval, but in this case the first robot hasdetected the third wireless message, and therefore has prepared a secondwaiting interval to ensure that the intruding message had finished,followed by a gate interval in which the first robot may finallytransmit its message at a randomly-selected time. The first robotinitially started with a relatively long WAIT interval so that otherrobots could have a chance, particularly those other robots that werepreviously forced to withhold their responses. The first robot thenprepared successively shorter wait intervals after each abortedresponse, to increase the likelihood that it will be able to transmit.The intent of the successively shorter wait intervals is to give thefirst robot an advantage relative to other robots that have not had towithhold their messages, but not to gain advantage relative to therobots that have already withheld their messages longer than the firstrobot. If all the robots adopt the same standards for the waiting andgating intervals, the method provides that each robot will get a turn,with those waiting the longest getting successively higher priority intiming.

In some embodiments, the initial hailing message may contain informationthat would allow other robots to filter their response. It may not makesense to try to localize certain other robots, or even to attemptcommunication with them. For example, the hailing message may includethe hailing robot's identification code, so that other robots that havealready localized that hailing robot can ignore the message. Forexample, “Hail, other robots! I'm ABC123. Please respond if you have notalready done so.” Other robots that have already localized ABC123 couldthen ignore the message.

In a similar way, the hailing message may contain information about thegeneral location of the hailing robot, such as “I'm at GPS coordinates1.234×5.678. Respond if you are near.” Then other robots receiving themessage may ignore it if they are sufficiently far away thatinterference is unlikely.

FIG. 23 is a sketch showing exemplary robots 2300 traveling in oppositedirections in a passageway, leading to a potential blockage situation.Fortunately, each robot 2300 includes a localization system according tothe present disclosure, and therefore can communicate specifically witheach other to resolve the crisis. Each robot includes a chassis 2309with wheels 2313 and a pole 2322 that extends above the cargo 2321 andsupports a wireless transceiver 2303, a 360-degree camera 2318, and alocalization signal emitter 2305. Each robot can then detect each otherrobot's localization signals and wireless messages, thereby determiningthe identification code and spatial location of each robot. With thatknowledge, the robots 2300 can communicate with each other and negotiateto find a resolution to the blockage problem, and can implement thesolution cooperatively. For example, in this case a solution may be forone group to form a single-file line along one side of the passagewayand the other group to form a single-file line along the other side, sothat the two groups could both pass by each other without conflict.

It is generally not necessary for any one of the robots 2300 to assume adominant role since they are capable, in the envisioned scenario, ofresolving the problem in a mutual, egalitarian fashion. However, if aparticular one of the robots, such as the first one to perceive theproblem, assumes a leadership role, the other robots may be configuredto not contest that role but rather to continue to cooperate inresolving the problem. In addition, if the robots cannot find a solutionafter a predetermined time, such as 1 second, then one or all of themcan contact a “supervisor” (not shown) which may be a central computeror a human, for example. The robots 2300 may relay the positions of thevarious robots to that supervisor so as to explain the problem at hand.The localization data may be especially important in this case, sincethe supervisor would be unlikely to offer helpful suggestions withoutknowing which robot is where spatially. With the location data andidentification code of each robot 2300, the supervisor can then directeach robot using wireless messages addressed to each robot specifically,thereby resolving the situation. Whether the situation is to be resolvedamicably by the robots themselves or by a supervisor, the location datafrom the localization systems on each robot are critical to finding anefficient solution.

As a further option, the robots 2300 may be configured to recordinterference events and other problems as they occur, and also to recordthe resolution achieved, thereby to resolve future similar problems moredirectly from the records. The robots 2300 may also be configured toconvey the problem data and the resolution to other robots that they maysubsequently encounter, so that the other robots can benefit from theexperience of the participating robots 2300. In this way, theparticipating robots 2300 may become “teacher” robots while the otherrobots that receive this information may “learn” from them. By sharingexperience in this way, the interconnected robots may develop a “hivemind” of shared experiences and mutually agreed solutions. In thepresent example, the hive mind solution may be simply “keep to yourright when traversing the passageway in either direction”, which wouldresolve future blockage problems without impeding traffic.

FIG. 24 is a sketch of exemplary robots adapted to tasks in theagriculture industry. A first robot 2401 is configured with a hoe 2423for weed control around crops 2431, and a second robot 2402 includes awater tank 2424 for irrigation. Both robots 2401-2402 includelocalization systems including wireless transmitter-receivers 2403,localization signal emitters 2405 positioned at the top of thetransmitter-receiver antennas 2403. Each robot 2401-2402 furtherincludes an imaging systems 2406 configured to image the other robot,items in the environment, and the localization signals emitted by otherrobots. The robots 2401-2402 are configured to maintain communicationwith each other and to monitor the spatial location of each other robotin range, by exchanging wireless messages and localization signals asdescribed herein. The robots 2401-2402 are also configured to image thecrops 2431 and other items in the environment such as weeds,obstructions, the farmer, etc. Also shown are boundary posts 2432demarking the edges 2433 of a field. Each boundary post 2432 includes apartial localization system including a localization signal emitter 2405atop a wireless transmitter-receiver 2403, but not a signal detectorsince it is not needed for the boundary posts 2432. The boundary posts2432 show how far the robots 2401-2402 can proceed without crossing theboundary 2433. In addition, each boundary post responds to a wirelessmessage such as a hailing message by transmitting a wireless messagethat includes the identification code of that boundary post, andsimultaneously emitting a localization signal, thereby indicating to therobots 2401-2402 which boundary post 2432 is located where. For example,a respective boundary post 2432 may be positioned at each end of eachrow of crops, and may be configured with a different identification codefor each, so that a robotic planter can align itself between theappropriate boundary posts 2432 in planting seeds at the properlocation. The irrigator robot 2402 can use the boundary posts 2432 tofollow a track between the rows, thereby avoiding running over the crops2431. Likewise the weeder robot 2401 may use the boundary posts 2432 asa guide in judging if a plant is a crop 2431 or a weed, since presumablythe crops 2431 are not located between the rows. The cameras 2406 on theweeder robot 2401 may also be used to distinguish weeds from crops.

FIG. 25 is a sketch showing exemplary maritime robots 2501-2502configured to clean up an oil spill 2534. Each robot 2501-2502 includesa wireless transceiver 2503, a sonic localization signalemitter/detector 2505, and imaging devices 2518. The various robots2501-2502 can directionally detect sonic localization signals emitted byother robots 2501-2502, and can image the other robots optically usingthe imaging devices 2518, and thereby localize each robot 2501-2502 insequence. In addition, each robot can determine the identification codeof each other robot 2501-2502 according to a wireless message receivedsynchronously with the localization pulse. The robots 2501-2502 canthereafter exchange specific messages to cooperate and to avoidinterfering with each other.

Also shown is an anchored buoy 2535 which also includes a localizationsystem including a localization signal emitter 2505 and a wirelesstransceiver 2503, but without imaging devices since imaging is notneeded in the non-mobile buoy 2535. The buoy 2535 may serve as a homingbeacon to guide robots 2501-2502 arriving from a shore station. The buoy2535 may also serve as a boundary marker to prevent the robots 2501-2502from drifting into travel lanes, among other functions. Alternatively,the buoy 2535 may include an imaging device, and may be configured tolocalize the various robots proximate to the buoy 2535, and may befurther configured to serve as a coordinator or supervisor by directingthe various robots using specific wireless messages to help them performtheir task efficiently or to avoid incoming traffic for example. Thebuoy 2535 may also be configured with higher power radio capability soas to communicate with a land-based station and to report on theprogress achieved or problems encountered.

FIG. 26 is a sketch showing a “swarm” or large number of independentexemplary helicopter-like flying drone robots 2601, each configured witha water tank 2624 for fighting a forest fire 2636 with water 2637. Eachdrone 2601 includes a localization system including a localizationsignal emitter 2605, a localization signal detector and imager 2606, anda wireless system 2603. Each drone 2601 is shown with a single propeller2627, but in a practical embodiment they are likely to have 4 or 6 or 8or more propellers 2627 for stability and greater lifting power. Sincethe drones 2601 fly in a three-dimensional space, the localizationsignal emitters 2605 and detectors 2606 may be configured to cover theentire 4π sphere of directions. This is in contrast to the horizontalangles or 360-degree azimuthal directions of interest to surface-boundrobots. Since the swarm of drone robots 2601 are configured to flyautonomously in close quarters and attack the fire 2636 in large numberstogether, it is important that they all communicate and keep track ofwhere each other robot 2601 is located three-dimensionally and inreal-time, with preferably centimeter precision at sub-second intervals.GPS would not serve, since it is too slow and not precise enough. Fromeach robot's perspective, the most important thing is to keep a safedistance from the other robots and avoid collisions. The geographicalposition of each robot is less important. Localization systems, asdisclosed herein, may be especially useful in managing a swarm-typeoperation by enabling three-dimensional localization of the other robotsrelative to each other, rather than according to a geographical map.

Also shown is a water supply tank 2625 with a recharging station 2626.Drones 2601 can return to the water supply tank 2625 to autonomouslyrefill their portable water tanks 2624, and can also stop at therecharging station 2626 when needed to recharge their batteries. Thewater supply tank 2625 and/or the recharging station 2626 may include alocalization signal emitter and wireless transmitter to guide the robotsback for resupply.

The swarm of flying drones may additionally be employed in othercooperative operations involving large outdoor areas, such as fieldspraying operations for weed or pest control, broadcast seeding andfertilization of soil for agriculture or post-fire recovery,environmental monitoring, and aerial surveying, among many otherapplications. Inter-drone localization and communication may beadvantageous in such applications to avoid midair collisions,cooperatively ensure coverage of areas not yet treated, avoid repeatingareas that have already been treated, detect targeted features of theland or vegetation, find and localize problem areas, and many otheradvantages. In addition, drone swarms with mutual localization andcommunication may be applicable to search-and-rescue operations such asfinding and localizing lost hikers, post-disaster victim search,earthquake damage assessment, and related applications. The localizationsystems and methods disclosed herein may enable the drones to detect andavoid interfering with non-drone vehicles such as human-piloted aircraftand emergency vehicles, thus avoiding a common hazard in chaoticpost-disaster scenarios.

FIG. 27 is a sketch of an indoor delivery application such as ahospital. Mobile robots 2701 are configured to transport cargo items2721 such as food trays, medicines, instruments, trash, patients, etc.Each robot 2701 includes a wireless system 2703, a large opticallocalization signal emitter 2705 spanning each side of the robot 2701,and a camera plus localization signal detector 2706 mounted on eachcorner of the robot 2701. Thus, each robot 2701 can exchangelocalization signals and wireless messages and thereby localize eachother including determining their identification codes. This isimportant since the robots 2701 are likely to encounter each otherfrequently in the crowded and kinetic environment of a health-carefacility, where interference must be avoided. Also, each robot 2701 maybe configured to alert the other robots 2701 as to the importance of thecargo 2721 for appropriate prioritization. For example, transporting adefibrillator instrument may be more time-critical than taking out thetrash. The other robots 2701 may then make way for the high-priorityitems as needed. It would be difficult to arrange such cooperationwithout the localization systems disclosed herein.

Also shown is a door 2738 leading, for example, to a patient room or thepharmacy for example. The door 2738 includes a localization system 2728positioned to help guide the robots 2701 to the intended destination.Especially in a hospital application, it is important to ensure that thecorrect robot 2701 finds the correct door 2738, to avoid misapplicationof medicines for example. The door-mounted localization system 2728 isconfigured to know which cargo 2721 is intended for that particular door2738 and thus serves as a redundant security gate. In addition, thedoor-mounted localization system 2728 may be configured to record datasuch as which robot 2701 with which cargo 2721 passed through the door2738 at what time, and in which direction, thereby providing a valuablesequence record of activities on the hospital floor.

In related applications, mobile robots having mutual localizationsystems as disclosed herein may be applicable to other delivery orsecurity applications involving large institutions. For example, in aprison, mobile robots can also deliver food trays to cells and retrievetrash without exposing staff. For security, mobile robots may circulatecontinuously to detect problems such as a door left ajar, prisonerspreparing to escape, a sick prisoner needing help, fights developing, orother illegal activity. The mobile robots may also detect maintenanceproblems such as a water leak or a burned-out light or clutter in apassageway before they become a security issue. In each suchapplication, the ability of the robots to localize each other and tocooperatively communicate may enable improved performance as well asavoided secondary problems such as robots interfering with or collidingwith each other.

FIG. 28 is a sketch showing numerous robots 2801 such as heavy equipmentin a quarry or strip-mining or road-building or other heavy outdooroperation. The robots 2801 may include dump trucks, steam shovels, waterand fuel tanks, and other mobile robots working the land. Humans aretypically excluded for safety reasons. Instead, each robot 2701 includesa localization system 2819, indicated as a star, by which the robot 2801can communicate with and cooperate with the other robots, therebycarrying out each task and managing the operation while avoidinginterference and collisions.

In large industrial operations such as a quarry, the localizationsystems 2819 may use high-frequency RF as the localization signal, andthe corresponding localization signal detectors may be directionalantennas or antenna arrays. The RF localization option may be feasiblewith large, high-power equipment as shown, and may be advantageous in alarge dirty noisy outdoor industrial site where localization signals arerequired to reach larger distances than could be reliably obtained with,for example, sonic signals. In addition, dust clouds may obscure opticallocalization signals such as visible or IR signals but have no effect onRF. Heavy-equipment robots 2801 generally have sufficient size forspaced-apart antennas to determine the direction of a high-frequency RFsignal, as well as ample power available. An exemplary all-RFlocalization system may include wireless communication in the usualHF-VHF range and localization signals in the higher-frequency UHF-THFrange. Alternatively, the wireless and localization signals may be inthe same band and use the same emitters and receivers. In oneembodiment, the wireless message itself serves as the localizationsignal, and each receiving robot is then configured to receive suchwireless messages and also determine their direction. Such an all-RFlocalization system would be immune to noise and dust, could readilycommunicate across hundreds of meters or more, and may be well-matchedto the requirements of a quarry site or other heavy construction sitewith numerous large and powerful machines at work.

Also shown is a watch-tower 2839 configured to monitor the variousrobots 2801 and redirect activities as needed. The watch-tower 2839 mayinclude a supervisory computer and/or a human manager depending on thetype of monitoring needed. The watch-tower 2839 includes a localizationsystem 2819 so that the supervisor can transmit a hailing message whenneeded, thereby causing the robots 2801 to report their location usinglocalization signals and their identity using wireless messages, onrequest. In this way the supervisor, either computer or human, can keeptrack of which robot 2801 is where in the quarry and which robot 2801 isdoing what task at each moment.

Also shown is a refueling station 2843 with a localization system 2819included so that the robots 2801 can find the refueling station andautonomously get re-fueled.

Another similar example is a road-grading and road-paving activity inwhich plows, graders, asphalters, rollers, line-painters, and the likemay be active autonomously. Likewise an earth-moving activity, such assite preparation before construction of a bridge or building, may employa swarm of heavy-equipment robots with mutual localization capabilityusing the disclosed systems and methods. Large constructions sites, suchas dam construction, highway overpass construction, high-rise buildingconstruction and the like, may advantageously employ mobile robots forhauling of concrete and other construction materials, removal of rocksand clutter, and delivery of non-robotic equipment where it is needed.Cooperative robots may also be employed in direct construction taskssuch as rebar welding, wood cutting, concrete laying or leveling orsawing or breakup, mortaring and setting cinder blocks or bricks,cutting or fastening light steel framing. positioning or drilling orbolting heavy steel structures, and many other tasks that requirecommunication and localization among autonomous robots.

FIG. 29 is a sketch of an automated factory scenario in which exemplarymobile and non-mobile robots cooperate using localization signals.Depicted is a non-mobile robot 2901 which includes a grasping tool 2929,an articulated (aimable) camera 2918, and a localization system 2919.Also shown are mobile robots 2902 configured as carts, which alsoinclude a localization system 2919. The non-mobile robot 2901 performs amanufacturing task in cooperation with the mobile robots 2902, such aslifting cans 2946 off of a conveyor belt 2944 and placing them on amobile robot 2902, and taking a scroll piece 2945 off of another mobilerobot and placing it on the conveyor belt 2944. Each mobile robot 2902brings the scroll pieces 2945 and then receives the cans 2946, thenscurries away to make room for the next mobile robot 2902. The mobileand non-mobile robots 2901-2902 use the localization systems 2919continually to manage the operation, avoid interference, arrange inputand output sequencing, adjust the positioning to be within reach of thegrasping tool 2929, and otherwise perform their respective tasks.

Additional applications in manufacturing, for autonomous mobile robotsas disclosed herein, may include devices to sort and count the finalproducts, then pack or box them and seal for final delivery, which mayinvolve cooperation with other robots that bring the products to thepacking robot, and other robots to collect the boxed goods for shipping.Yet other robots may be tasked with receiving components, unboxing andcounting them, then sorting or storing or arranging for another robot totransport the components to an assembly station where they are needed bya third robot for assembly into the final product. In each case,cooperation among the interacting mobile and non-mobile robots may beenhanced by the ability to specifically communicate with other localizedrobots using the systems and methods disclosed herein. Indeed, manycooperative tasks among autonomous robots may be impossible without suchlocalization.

FIG. 30 is a sketch showing a busy automated trans-shipment center suchas a postal service center, an overnight carrier hub, a productfulfillment warehouse, or other logistical center handling large numbersof items with large numbers of mobile robots in cooperation, each withan exemplary localization system 3019 according to the presentdisclosure. Depicted are mobile robots configured as carts 3009 adaptedto transport loose goods such as unsorted letters, stacked or boxedgoods such as sorted letters, or other items of any description. Alsoshown are pallet movers 3047 configured to move pallets of goods andoptionally to lift packages or pallets onto shelving 3048 or othervertical or horizontal storage areas. A weighing station 3048 isconfigured to weigh a mobile robot such as a cart 3009 plus its burden,and then to subtract the weight of the cart 3009. However, each cart3009 may have a different weight. Therefore, the weighing station needsto know which cart 3009 is involved, in order to arrive at an accuratenet weight. Accordingly, each cart 3009, pallet mover 3047, and fixeditem 3048-3049 is equipped with a localization system 3019 depicted as astar. The localization systems 3019 enable each mobile robot 3009-3047to communicate and cooperate with each other, and to correctly locateeach fixed asset 3048-3049 by communicating them specifically. Forexample, the weighing station 3048 communicates with whichever cart 3009is currently being weighed to determine its identification code, andthen using a stored correlation table, the weighing station 3048subtracts the known weight of that particular cart 3009 from the grossweight to obtain the correct net weight of the goods.

A similar application may be a sawmill in which cooperating robots aretasked with unloading logs from logging trucks (which may behuman-driven or autonomous), sizing and grading the logs, scanning themfor metal or rocks, then providing them to an autonomous sawingoperation. Further robots may collect the sawn lumber, sort and stack itin a drying kiln or outdoor rack, and then collect the dried product.Further robots may be tasked with chipping the trimmings and pressinginto particle-board. At each station, multiple mobile and fixed-siterobots interact to process the goods, which requires the closecooperation in positioning and timing that may be provided by thelocalization systems and methods disclosed herein.

FIG. 31 is a sketch of an airport including various vehicles and robotswith exemplary localization systems included. At an airport, there aretypically multiple vehicles moving around, presenting a continual riskof a collision. Aircraft 3101 are taxiing to and from the runway,baggage trains 3102 and other vehicles are streaming between aircraftand terminal, with fuel trucks and food trucks and sanitation trucksmoving independently around the tarmac, all of which represent a complexhazard. Greatly enhanced safety can be obtained by installing alocalization system 3119 according to the present disclosure, depictedas a star on each vehicle 3101-3102, so that they can maintain real-timeawareness of the other vehicles in proximity. Then, if one of thevehicles detects an imminent collision with a second vehicle, the firstvehicle can send an emergency wireless message specifically to thesecond vehicle, causing the second vehicle to sound a collision alarmwhich causes the driver of the second vehicle to stop. Alternatively,the second vehicle may be configured to respond automatically to such anemergency wireless message addressed specifically to the second vehicle,for example causing the second vehicle to stop automatically. In thisway an unnecessary collision may be avoided.

In addition, most or all of the vehicles at an airport are likely tobecome autonomous in the future, with the driver of each vehicle(baggage haulers, food trucks, etc.) being replaced by autonomousprocessors. Without a human driver in control, the need for closecooperation with localization will be even more critical. Thelocalization systems are needed to provide location data on eachvehicle, enable specific wireless communication between them, and avoidmany ground hazards.

Also shown are location markers 3132 which include localization systems3119 and are configured to assist aircraft 3101 and other vehicles 3102to remain within marked lane boundaries 3133 by exchanging wirelessmessages and localization signals. A control tower 3139, configured witha localization system 3119, can manage ground operations by localizingand identifying each aircraft or vehicle 3101-3102 and recognizepotential hazards in time to avoid them.

In addition, cooperating mobile robots may be employed for baggagehandling operations, such as sorting and transporting baggage depositedby passengers at check-in, transporting to an inspection station forscanning and the like, then stacking of baggage into containers for easyloading onto planes. Upon arrival, further robots may then separate thebags in the terminal and place them gently onto belts for passengers toretrieve. At each stage of the baggage handling operations, coordinationbetween the robots would be greatly enhanced by the ability to identify,localize, and specifically communicate with each other robot with whichit interacts.

FIG. 32 is a schematic showing a common problem when a prior-artemergency vehicle 3200 such as a fire engine is blocked by otherprior-art vehicles 3201-3202 which are stopped at a stoplight 3203. Thestopped vehicles 3201-3202 may be autonomous or human-driven. On aroadway, this blockage problem generally does not occur because humandrivers and autonomous vehicles have been taught to pull to the rightand stop, thereby letting the emergency vehicle pass by. But at astoplight 3203, most drivers are reluctant to dash across theintersection or take any other action while sirens are sounding, unlessspecifically directed to do so. Autonomous vehicles are also generallyprogrammed not to move until the emergency situation has lifted. Manyemergency vehicles are equipped with strobe lights that flash at aparticular frequency, and many traffic signals are configured to respondto the strobe flashes by turning green toward the emergency vehicle andred everywhere else. However, this is NOT sufficient to prompt mostdrivers or autonomous vehicles to move or take any action on their owninitiative. Careful drivers have no way of knowing whether the greenlight means they should dash forward or that it has simply cycled togreen. Any action could be the wrong action, which might lead to acollision if another emergency vehicle is approaching from a differentdirection. Lacking means for specifically communicating with the stoppedvehicles 3201-3202, the emergency vehicle 3200 remains blocked.

FIG. 33 shows how the blockage problem can be resolved using the systemsand methods disclosed herein. Again a fire engine 3300 is approaching anintersection blocked by vehicles 3301-3302, however now each vehicle3300-3302 includes a localization system 3319 indicated by a star. Theemergency vehicle 3300 quickly establishes communication with each ofthe other vehicles 3301-3302, and then orders them to proceed. Forexample, the emergency vehicle 3300 may instruct the first vehicle 3301to go ahead and turn left, and may instruct the second vehicle 3302 toproceed forward and then pull over to the right. This would immediatelyopen up a path for the emergency vehicle 3300 to proceed, as indicatedby dashed arrows.

In addition, the stoplight 3303 may further include a localizationsystem so that the emergency vehicle 3300 could control it to reinforcethe instructions to the vehicles 3301-3302. For example, when theemergency vehicle 3300 instructs the first vehicle 3301 to turn left,the emergency vehicle 3300 could simultaneously turn on the left greenarrow and make it flashing to show that it is safe for the first vehicle3301 to proceed left. After instructing the second vehicle 3302 to moveforward, the emergency vehicle 3300 could control the stoplight 3303 andmake the green light flash to again reinforce the instructions. Then,after passing through the intersection, the emergency vehicle may thencause the stoplight 3303 to turn red in all directions for a fewseconds, thereby to prevent other people from chasing the emergencyvehicle (a common unsafe sport). The red light period would also givethe other two vehicles 3301-3302 a chance to return to lanes withoutbeing pressured by approaching traffic.

An additional emergency operation involving autonomous vehicles may beto contain an escaping criminal in a high-speed chase scenario.Human-driven vehicles are generally not allowed to closely approach thespeeding vehicle, due to safety concerns. Consequently, in some cases, ahighway chase may last hours and span large distances, continuallyplacing other motorists at risk. In some cases, officials may have tolet the escapee go rather than place others at risk. In such cases, aset of autonomous vehicles with mutual cooperation may advantageously beemployed to surround the speeding vehicle, by positioning in front andbehind and both sides, then gradually slow to a stop in closecoordination, thereby forcing the escaping vehicle to stop as well. Withsuch a maneuver, the autonomous vehicles may bring the chase to a rapidand safe conclusion.

The localization systems and methods disclosed herein can providenumerous benefits not available heretofore, by enabling each mobilerobot in a cohort of mobile robots to determine the identity and spatiallocation of other robots, and to communicate specifically with each ofthe other robots, and to cooperatively manage tasks and resolveproblems.

The system and method may be fully implemented in any number ofcomputing devices. Typically, instructions are laid out on computerreadable media, generally non-transitory, and these instructions aresufficient to allow a processor in the computing device to implement themethod of the invention. The computer readable medium may be a harddrive or solid state storage having instructions that, when run, orsooner, are loaded into random access memory. Inputs to the application,e.g., from the plurality of users or from any one user, may be by anynumber of appropriate computer input devices. For example, users mayemploy vehicular controls, as well as a keyboard, mouse, touchscreen,joystick, trackpad, other pointing device, or any other such computerinput device to input data relevant to the calculations. Data may alsobe input by way of one or more sensors on the robot, an inserted memorychip, hard drive, flash drives, flash memory, optical media, magneticmedia, or any other type of file—storing medium. The outputs may bedelivered to a user by way of signals transmitted to robot steering andthrottle controls, a video graphics card or integrated graphics chipsetcoupled to a display that maybe seen by a user. Given this teaching, anynumber of other tangible outputs will also be understood to becontemplated by the invention. For example, outputs may be stored on amemory chip, hard drive, flash drives, flash memory, optical media,magnetic media, or any other type of output. It should also be notedthat the invention may be implemented on any number of different typesof computing devices, e.g., embedded systems and processors, personalcomputers, laptop computers, notebook computers, net book computers,handheld computers, personal digital assistants, mobile phones, smartphones, tablet computers, and also on devices specifically designed forthese purpose. In one implementation, a user of a smart phone orWiFi-connected device downloads a copy of the application to theirdevice from a server using a wireless Internet connection. Anappropriate authentication procedure and secure transaction process mayprovide for payment to be made to the seller. The application maydownload over the mobile connection, or over the WiFi or other wirelessnetwork connection. The application may then be run by the user. Such anetworked system may provide a suitable computing environment for animplementation in which a plurality of users provide separate inputs tothe system and method. In the below system where robot controls arecontemplated, the plural inputs may allow plural users to input relevantdata at the same time.

It is to be understood that the foregoing description is not adefinition of the invention but is a description of one or morepreferred exemplary embodiments of the invention. The invention is notlimited to the particular embodiments(s) disclosed herein, but rather isdefined solely by the claims below. Furthermore, the statementscontained in the foregoing description relate to particular embodimentsand are not to be construed as limitations on the scope of the inventionor on the definition of terms used in the claims, except where a term orphrase is expressly defined above. Various other embodiments and variouschanges and modifications to the disclosed embodiment(s) will becomeapparent to those skilled in the art. For example, the specificcombination and order of steps is just one possibility, as the presentmethod may include a combination of steps that has fewer, greater, ordifferent steps than that shown here. All such other embodiments,changes, and modifications are intended to come within the scope of theappended claims.

As used in this specification and claims, the terms “for example”,“e.g.”, “for instance”, “such as”, and “like” and the terms“comprising”, “having”, “including”, and their other verb forms, whenused in conjunction with a listing of one or more components or otheritems, are each to be construed as open-ended, meaning that the listingis not to be considered as excluding other additional components oritems. Other terms are to be construed using their broadest reasonablemeaning unless they are used in a context that requires a differentinterpretation.

What is claimed is:
 1. A system, mounted on a first robot, forlocalizing a second robot, comprising: a wireless transmitter configuredto transmit a first wireless message; a localization signal emitterconfigured to emit a first localization signal comprising pulsed visibleor infrared light synchronized with the first wireless message; awireless receiver configured to receive a second wireless message fromthe second robot; a localization signal detector configured to detect,and to determine an arrival direction of, a second localization signalfrom the second robot, the second localization signal comprising pulsedvisible or infrared light synchronized with the second wireless message;and a processor configured to cause the localization signal emitter toemit the first localization signal synchronously with the first wirelessmessage, to determine a direction toward the second robot based at leastin part on the arrival direction of the second localization signal, andto associate the second localization signal and the direction toward thesecond robot with the second wireless message.
 2. The system of claim 1,wherein the first wireless message includes a first predeterminednon-transient identification code associated with the first robot, andthe second wireless message includes a second predeterminednon-transient identification code associated with the second robot. 3.The system of claim 1, wherein the processor is further configured toperform one or more of the following steps: determine which particularrobot, among a plurality of other robots, is the second robot based atleast in part on the direction toward the second robot, as determinedfrom the arrival direction of the second localization signal; decode asecond identification code by analyzing the second localization signal;identify the second robot by comparing an image of the second robot andthe direction toward the second robot; form a plurality of successiveimages of the second robot at successive times, and calculate an updateddirection toward the second robot based on at least two of the pluralityof images; communicate with the second robot after determining both thedirection toward the second robot and a pre-determined non-transientidentification code associated with the second robot; determine, basedat least in part on one or more communications with the second robot,whether an imminent collision is avoidable or unavoidable; avoid, incooperation with the second robot, an imminent collision, if suchavoidance is possible or cause the second robot to avoid an imminentcollision, at least in part by communicating with the second robot, ifsuch avoidance is possible and necessary; wherein the avoid, incooperation with the second robot, an imminent collision, or the causethe second robot to avoid an imminent collision, includes the followingsteps: avoid interference between the first and second robots bycommunicating wirelessly with the second robot after detecting thesecond localization signal and determining, according to the arrivaldirection of the second localization signal, which robot, among aplurality of robots proximate to the first robot, is the second robot;determine a second predetermined non-transient identification codeconfigured to persistently represent the second robot specifically, andthen transmit, specifically to the second robot, a wireless message thatincludes the second identification code; determine whether the secondrobot includes a localization system comprising a second localizationsignal emitter configured to emit the second localization signal, and asecond localization signal detector configured to determine an arrivaldirection of the first localization signal; prepare, in cooperation withthe second robot, a first sequence of actions comprising a plurality ofsequential positive accelerations, active or passive decelerations,waiting times, or steering actions of the first robot, and a secondsequence of actions comprising a plurality of sequential positiveaccelerations, active or passive decelerations, waiting times, orsteering actions of the second robot; avoid a collision, at least inpart by communicating with the second robot after determining thedirection toward the second robot and a pre-determined non-transientidentification code which is persistently associated with the secondrobot; communicate with the second robot, and prepare, at least in partbased on communications with the second robot, one or more sequences ofactions configured to avoid the collision or to minimize the harm of anunavoidable collision, and to implement a selected one of the sequencesof actions; wait, after receiving a wireless message from the secondrobot, for a predetermined waiting interval, and then prepare a gateinterval, and transmit a responsive wireless message at a randomlyselected time during the gate interval; and delay emitting the firstlocalization message while another wireless message is in progress. 4.The system of claim 3, wherein the processor is configured to wait,after receiving a wireless message from the second robot and determiningthat another wireless message has been transmitted during thepredetermined waiting interval, for a second waiting interval, and thento prepare a second gate interval, and to emit a wireless message duringthe second gate interval.
 5. The system of claim 4, wherein the secondwaiting interval is shorter than the predetermined waiting interval. 6.The system of claim 1, further including a visible-light or infraredcamera configured to create an image of robots proximate to the firstrobot and of a particular localization signal comprising visible lightor infrared pulses emitted by a particular one of the robots proximateto the first robot.
 7. The system of claim 1, wherein the first wirelessmessage includes a first predetermined non-transient identification codepersistently associated with the first robot, and the second wirelessmessage includes a second pre-determined non-transient identificationcode associated with the second robot, and the processor is furtherconfigured to associate the second identification code with the secondrobot.
 8. The system of claim 1, wherein the first localization signalbegins when the first wireless message ends, or the first wirelessmessage begins when the first localization signal ends, or the firstlocalization signal and the first wireless message are present at thesame time, or the first localization signal is emitted responsive to apredetermined icon in the first wireless message.
 9. The system of claim1, wherein the localization signal emitter is configured to emit thefirst localization signal in temporal proximity to the first wirelesssignal.
 10. The system of claim 1, wherein the localization signalemitter is configured to encode a first identification code in the firstlocalization signal comprising a plurality of visible light or infraredpulses, by modulating a width of each pulse or by modulating intervalsbetween the pulses.
 11. The system of claim 1, wherein the localizationsignal emitter is configured to emit the first localization signal suchthat the first localization signal is detectable to other robotsproximate to the first robot regardless of the position of the otherrobots.
 12. The system of claim 11, wherein the first localizationsignal has azimuthal symmetry or spherical symmetry.
 13. The system ofclaim 1, wherein the first identification code is encoded in the firstlocalization signal.
 14. The system of claim 1, wherein the system ismounted on an unoccupied drone, an unoccupied aircraft, an unoccupiedhelicopter, an unoccupied hovercraft, an unoccupied underwater vehicle,an unoccupied submarine, an unoccupied mini-sub, an unoccupiedsubmersible mobile device, or other unoccupied self-propelled devicecapable of moving in two or three dimensions.
 15. The system of claim 1,wherein the second localization signal comprises a plurality of pulsesand the localization signal detector is configured to separately detecteach pulse in the plurality of pulses, and to determine therefrom anon-transient identification code uniquely and persistently associatedwith the second robot.
 16. The system of claim 1, wherein thelocalization signal detector is configured to form an image thatincludes both a representation of the second robot and a representationof the second localization signal.
 17. The system of claim 1, whereinthe localization signal detector is an imaging detector configured toform a localization signal image that images the second localizationsignal, and wherein the system includes a second imaging detectorconfigured to form an image that images the second robot.
 18. The systemof claim 17, wherein the processor is configured to associate the secondlocalization signal with the second robot according to a spatialassociation of the localization signal image and the image of the secondrobot.
 19. The system of claim 1, wherein the localization signaldetector comprises one or more imaging detectors mounted on the firstrobot.
 20. The system of claim 1, wherein the localization signalemitter comprises one or more visible light or infrared energy emittersmounted on the first robot.
 21. The system of claim 1, wherein the firstwireless message includes a request for other robots to respond to thefirst wireless message by transmitting visible light or infraredlocalization signals.
 22. The system of claim 1, wherein each visiblelight or infrared pulse of the first and second localization signal hasa duration of 1 nanosecond to 100 milliseconds.
 23. A robot configuredto transmit a wireless message concurrently with a localization signalcomprising one or more pulses of visible and infrared light.
 24. Therobot of claim 23, wherein the wireless message includes a non-transientidentification code that is persistently, specifically, and uniquelyassociated with the robot.
 25. A first robot configured to determinewhich particular robot, among a plurality of robots proximate to thefirst robot, is associated with a particular identification code bydetecting and determining an arrival direction of one or more visiblelight or infrared emitted by the particular robot, wherein theparticular identification code is encoded in the one or more visiblelight or infrared pulses, or is encoded in a wireless messagetransmitted synchronously with the one or more visible light or infraredpulses.
 26. A system comprising: a wireless transmitter configured totransmit a wireless message including a predetermined firstnon-transient identification code; a localization signal emitterconfigured to emit a first localization signal comprising pulsedinfrared or visible light; a processor configured to cause thelocalization signal emitter to emit the first localization signal suchthat the first localization signal has a temporal relationship with thefirst wireless message; a wireless receiver configured to receive asecond wireless message and to detect a predetermined secondnon-transient identification code therein, the second identificationcode being associated with a particular robot among a plurality ofrobots proximate to the system; a localization signal detectorconfigured to detect a second localization signal comprising pulsedinfrared or visible light and to determine an arrival direction of thepulsed infrared or visible light; a camera configured to image theplurality of robots proximate to the system; and a processor configuredto determine, by comprising the arrival direction to the plurality ofrobots in the image, which robot, among the plurality of robots, isassociated with the second identification code.
 27. The system of claim26, further comprising a processor configured to determine when a thirdrobot has come within range of the system, and to responsively transmita hailing wireless message that includes the first identification codeand an offer to communicate by emitting a localization signal comprisingone or more pulses of infrared or visible light.
 28. The system of claim27, further comprising a processor configured to detect an imminentcollision with a human-driven vehicle that includes an automaticemergency intervention system, and to responsively transmit a particularwireless message to the human-driven vehicle that activates theautomatic emergency intervention system.
 29. The system of claim 1,wherein: the first localization signal includes the first identificationcode encoded therein, the first identification code comprising apredetermined non-transient code that specifically and uniquelyidentifies the first robot; and and the second localization signalincludes the second identification code encoded therein, the secondidentification code comprising a predetermined non-transient code thatspecifically and uniquely identifies the second robot.
 30. The system ofclaim 1, further including one or more cameras mounted in or on thefirst robot and configured to produce an image that includes both thesecond robot and the second localization signal in the image.